Musculoskeletal Functional Human Anatomy

[하우헬스]

MUSCULOSKELETAL FUNCTIONAL HUMAN ANATOMY

INTRODUCTION

The starting positions (anatomical, fundamental).  All descriptions in human anatomy are expressed in relation to the anatomical position.  A person is in anatomical position when they stand erect with the head facing straight ahead, the arm at the side with the palms of the hands also facing anterior.  The lower extremities are together with the toes pointing straight ahead.  The fundamental position is the same except that the palms of the hands dace medially toward the thighs.

PLANES OF THE BODY

1. Sagittal plane

• Divides body into right and left halves.

• Forward and backward motions (flexion, extension).

• Rotary motion in sagittal plane occurs around a coronal (X) axis.

2. Frontal (coronal) plane

• Divides body into front and back halves.

• Side-to-side movements or lateral/medial movements (abduction, adduction,    

   radial/ulnar deviation, lateral flexion).

• Rotary motion in frontal plane occurs around an anterior-posterior (Z) axis.

3. Transverse (horizontal) plane

• Divide body into superior (upper) and inferior (lower) halves.

• Movements occur parallel to ground (rotary motions, horizontal abduction/adduction).

• Rotary motion in transverse plane occurs around a longitudinal or vertical (Y) axis.

MOVEMENT TERMINOLOGY

• Flexion: movement in the sagittal plane, from anatomical position.

• Extension: movement in the sagittal plane, back to anatomical position.

• Abduction: movement in the frontal plane, away from the midline of the body or                                        

                     segment.

• Adduction: movement in the frontal plane, toward the midline of the body or segment.

• External rotation: movement in the transverse plane, reference point turns away from       

                               midline or reference point of the body.

• Internal rotation: movement in the transverse plane, reference point turns toward the

                              midline or reference point on the body.

• Horizontal abduction: movement in the transverse plane, away from the midline of the

                                       body (used for hip and shoulder).

• Horizontal adduction: movement in the transverse plane, toward the midline of the

                                       body (used for hip and shoulder).

• Lateral flexion: movement in the frontal plane, away from the midline of the body           

                            (neck/trunk).

• Inversion: foot movement, reference segment moves toward midline.

• Eversion: foot movement, reference segment moves away from midline.

• Supination (foot movement): triplanar combination of inversion, adduction, and                                     

                                                  plantar flexion.

• Supination (forearm movement): turning the palm of the hand up.

• Pronation (foot movement): triplanar combination of eversion, abduction, and                                  

                    dorsiflexion

• Pronation (forearm movement): turning the palm of the hand down.

• Plantar flexion: foot movement towards the plantar surface.

• Dorsiflexion: foot movement towards the dorsal surface.

• Protraction: movement of a segment anteriorly.

• Retraction: movement of a segment posteriorly.

ANATOMICAL TERMINOLOGY

Most anatomical terms are derived from Lain and/or Greek.  These terms are usually made up of combinations of four elements.  These elements are the word root, the combining form, the prefix, and the suffix.

• The word root is the subject or main part of the word.
• The combining form for most anatomical terms is the vowel o.
• A prefix is added to the beginning of a word root to change its meaning.
• A suffix is added to the end of a word root or combining form to change its meaning.

Word Roots

adip – fat                                                                alg – pain                                                               

angi – vessel                                                           arthr – joint                                                            

bio – life, living                                         brachi – arm                                                           

capit – head                                                            cardi, cardia, cardio – heart                                   

caud – tail                                                               cephal – head                                                         

cerebro – brain                                           chondr – cartilage                                                  

cry, cryo – cold                                          cut – skin                                                               

cyt, cyto, cyte – cell                                               derma, demato – skin                                            

dors – back                                                             ede – swell                                                             

endo – within                                                         gastro – stomach                                                    

gloss – tongue                                                         hem, hemat – blood

hepar, hepato – liver                                               hist – tissue

hydr – water                                                           ilio – ilium

lip – fat                                                      meningo – membrane

my – muscle                                                            necr – corpse, death

nephr – kidney                                                        oculo – eye

ophthalm – eye                                          oss, oste – bone

path – disease                                                         ped – child

pod – foot                                                               psych – mind, soul

soma, somato – body                                              spas – draw, pull

therap – treatment                                                  tox – poison

Prefixes

a, ab, abs – away from                              a, an – negative, no, not, without                          

ad – to, toward                                                       aer – air                                                     

amb – both, on both sides                                      amph – around, on both sides                               

ante – before                                                           anti – against                                                         

bi, bis – twice, double                                            brachy – short, around                                           

co, col, com, co – with, together               contra – against, counter                          

di, diplo – two, double                              dia – through, between                            

dis – negative, separation, apart                dys – bad, painful, difficult                                  

e, ec, ex – out, out from, our of                ecto, exo – outside                                                 

em, en – in, on                                                        end – inside                                                           

epi – upon, on, above                                              hemi – half        

heter – other, difficult                                            homeo, homo – same, similar      

hyper – beyond, excessive                                      idio – self, one’s own, separate

infra – beneath                                                        inter – among, between               

iso – equal, like                                          macro – large, great                                  

mal – bad, abnormal                                               med, medi – middle                                 

mega, megal – great, large                                      micro – small                                            

neo – new                                                               ortho – straight, normal               

para – near, beside, apart from                  per – through                                            

peri – around                                                          poly – much, many                                                

post – after, behind                                                pre, pro – before, on front of                                 

pseudo – false                                                         retro – backward, located behind                          

semi – half                                                              sub – under, beneath, below                                  

super – above, over                                                 sym, syn – with, together, jointed                         

tachy – rapid                                                           trans – across, through, beyond               

tri - three

Suffixes

-able – capable of, having ability to                                    

-ac, -al – pertaining to                                                         

-ary – connected                                                                 

-asis, -asia, -esis, -osis – condition or state of                     

-cel, -cele – swelling, enlarged space, tumor                      

-cid, -cide, -cis – cut, kill, destroy                                      

-emia – condition of blood                                                 

-ferent – carry                                                                                  

-form – shape                                                                      

-ia – state, condition; indicates a noun ending                        

-ic – indicates an adjective ending

-ism – condition, state

-ist – specialist

-itis – inflammation

-logy, -ology – the study of

-malacia – softening

-oma – tumor

-ory – pertaining to

-ose – tumor

-pathy – disease

-penia – deficiency

-pnea – to breathe

-tomy – cutting into, incision into

-trophy – state relating to nutrition or growth

-tropic – turning toward, changing influencing

General Terminology

anterior – the front of

posterior – the back of

ventral (volar) – the front of

dorsal – the back of

proximal – general term meaning nearer to

distal – general term meaning farther from

lateral – general term meaning farther from midline

medial – general term meaning nearer to midline

superior – higher

inferior – lower

cranial – head

caudal – tail

plantar – the sole of the foot

dorsum – the top of the foot

bilateral – present on both sides

ipsilateral – on the same side

contralateral – on the other side

symmetrical – the same on both sides

asymmetrical – not the same on both sides

supine – lying, face up

prone – lying, face down

BONE

Functions of Bone

1. Support: provides support to the soft tissue, attachments for muscles and gives                the body its basic shape.                                                                                                                    

2. Movement: bones provide the lever systems of the body and muscle attachment required to produce locomotion.                                                                                                    

3. Protection: most internal organs are protected by the skeleton (i.e. cranium, ribs and pelvis).                                                                                                                                              

4. Meneral storage: such as calcium, sodium, potassium, phosphorus and magnesium.

5. Hemopoiesis: the red marrows of certain bones produce both red and white blood cells.
 

Classification of Bones

1. Long bones: most bones of the appendicular skeleton (i.e. humerus, radius, ulna, femur, tibia, metacarpal, metatarsal, and phalanges).

2. Short bones: carpals and tarsals.

3. Flat bones: parietal, frontal, occipital, ribs, and sternum.

4. Irregular bones: don’t fit another category (i.e. vertebrae, the pelvic)

Structure of Bone

2 types of tissue contained in all bones: compact bone and spongy bone.

1. Gross anatomy of a long bone
1. Diaphysis: the shaft
2. Epiphysis: expanded area at ends of bone
3. Growth plate: interface between diaphysis and epiphysis.
• Matrix is added here to increase bone length, until puberty when plate seals in response to hormones.
2. Matrix of bone
1. Composed of an organic and inorganic portion
2. Cell types originate from undifferentiated stem cell: osteoprogenitor
• Osteoblasts: build up bone and form osteocytes, mature bone cells
• Osteoclasts: break down bone
  
  

3. Organic component
• Osteocytes and collagen.
• Gives bone flexibility/tensile strength
   
4. Inorganic component
• Hydroxyapatite (formed from calcium and phosphate) gives bone its hardness  

JOINTS

Classifications                                                                                                                             1. Synarthrotic                                                                                                                                  2. Amphiarthrotic                                                                                                                                  3. Diathrotic

Synarthrotic

•     No movement, no joint capsule, fastened by hyaline cartilage

                            A.            Sutures

• Between bones in skull
1. Gomphosis
• Between teeth and jaws
2. Synchodrsis
• Epiphyseal plates

Amphiarthrotic

•     Slightly movable, bones united by cartilage

                            A.            Sydesmosis

             §   Between shafts of fibula and tibia

             §   Between shafts of radius and ulna

                             B.            Symphysis

             §   Broad, flattened discs between vertebrae  

Diarthrotic

•     Also called synovial joints

•     Freely movable, join 2 bones within a joint capsule

1. Unique characteristics of synovial joints
1. Articular cartilage
• Covers ends of articulating bones
• Is slick, reduces friction

2. Synovial membrane
• Lines cartilage and joint capsule
• Secretes synovial fluid
3. Synovial fluid
• Thick, viscous fluid fills space between articulating bones
• Serves to lubricate joint and provide shock absorption
4. Joint capsule
• Contains synovial fluid within joints
5. Supporting ligaments
• Provide additional support to these freely movable joints
   
1. Types of synovial joints:
1. Gliding: between carpal and tarsal bones
2. Hinge: elbow, knee, and ankle
3. Pivot: between ends of radius and ulna
4. Ellipsoid: between radius and carpal bones
5. Saddle: between carpal bones and phalanges
6. Ball and socket: shoulder and hip joints
    

 

ANKLE AND FOOT

1. Ankle joint, or talocrural joint, is a hinge joint that is formed by an articular facet on the distal extremity of the tibia, which articulates with the superior articular surface (trochlea) of the talus; the medial malleolus, which articulates with the medial surface of the trochlea of the talus; and the lateral malleolus.

2. The foot is comprised of the 7 tarsal bones, 5 metatarsals, 14 phalanges, and 2 sesamoid bones.

3. The foot is separated into three instinct segments: the forefoot (5 metatarsals and 14 phalanges), the midfoot (navicular, cuboid, and 3 cuneiforms), and the hindfoot (calcaneus and talus).

The Ankle

A.  The talus

1.      A tarsal bone.

2.      Primary articulation site for the tibia.

§  The talus transmits most of the body's weight from the tibia to the foot.

3.      The talus also articulates with the lateral malleolus of the fibula.

4.      Ligaments extend from the lateral sides of the talus to the tibia and fibula.

§  Laterally: anterior talofibular, calcaneofibluar, and posterior talofibular ligaments.

§  Medially: deltoid complex (consisting of 4 ligaments: anterior talotibial, tibionavicular, calcaneotibial, and posterior talotibial ligaments).

B.  The 7 tarsal bones

1. Talus.                                                                                                                           2. Calcaneus (the heel bone).                                                                                     3. Cuboid (lateral side).                                                                                          4. Navicular (medial side).                                                                               5. Cuneiforms: medial (1^st), intermediate (2^nd), and lateral (3^rd).

The Foot

A.  The 5 metatarsals

1.      Form the sole of the foot

2.      First metatarsal is medial; fifth metatarsal is lateral  

B.  The 14 phalanges

1.       Form the toes.                                                                                           2.       Each toe has 3 phalanges (proximal, intermediate, and distal).

• Exception is the big toe (also called the hallux), which has only 2 phalanges.

C.  Arches of the foot

1. Medial Longitudinal Arch

• Formed by the calcaneus – talus – navicular - three cuneiforms - metatarsals 1-3.
• Supported by the calacaneonavicular ligament (also called the spring ligament).
• When the spring ligament weakens there is a tendency for foot to pronate.
• Supported by the tibialis anterior.

2. Lateral Longitudinal Arch

• Formed by the calcaneus – cuboid - metatarsals 4-5.
• Supported by the peroneus longus.

                              3. Transverse Arch

§  Formed by the talus – navicular – cuboid – cuneiforms 1-3.

§  Plantar aponeurosis (fascia which originates at the calcaneous and spreads forward to base of metatarsals at sole of foot).              

                                 4. Anterior Metatarsal Arch

• Formed by the distal heads of metatarsals.

 

 

 

 

 

 

 

 

Muscles of the Foot (Intrinsic Muscles)

             A. First Layer

1. Flexor digitorum brevis
• Flexes the MTP and PIP joints of the four lateral toes.
2. Abductor hallucis
• Abducts the MTP joint of the big toe (hallux). 
3. Abductor digiti minimi
• Abducts the MTP joint of the fifth (little) toe.

            

B. Second Layer

1. Quadratus plantae
• Assists with flexion of the MTP, PIP, and DIP joints of four lateral toes.
2. Lumbricales
• Flex the MTP joints and extend the PIP and DIP joints of the four lateral toes.

 

C. Third Layer

1. Flexor hallucis brevis
• Flexes the MTP joint of the big toe.
2. Adductor hallucis
• Adducts the big toe. 
3. Flexor digiti minimi brevis
• Flexes the MTP joint of the fifth toe.

 

D. Fourth Layer

1. Dorsal interossei
• Abduct the third and fourth MTP joints.
2. Plantar interossei
• Adducts the third, fourth, and fifth MTP joints. 

E. Dorsal Intrinsic Muscles of the Foot

1. Extensor digitorum brevis
• Extends the MTP, PIP, and DIP joints of the 2^nd-4^th toes.
2. Extensor hallucis brevis
• Extends the MTP and IP joints of the big toe.

 

 

LOWER LEG

The two bones of the lower leg are the tibia (medial bone) and the fibular (lateral bone).  The prominence at the distal of the tibia is known as the medial malleolus and the prominence at the distal end of the fibula is known as the lateral malleolus.  

Muscles of the Lower Leg

A.   Anterior Compartment

1.   Tibialis anterior                                                                       

§  Dorsiflexes ankle and inverts foot.

2. Extensor hallucis longus                                                                        

§  Dorsiflexes ankle and inverts foot, and extends MP and IP joints of the big toe.

3.   Extensor digitorum longus                                                                    

§  Dorsiflexes ankle and everts foot, and extends MP, PIP, and DIP joints of the four lateral toes.

B.   Lateral Compartment

1.      Peroneus  longus                                                                     

§  Everts foot and plantar flexes ankle.

§  Tendon around lateral malleolus of the fibular.

§  Supports the lateral longitudinal arch.

2.      Peroneus brevis                                                                    

§  Everts foot and plantar flexes ankle.

§  Tendon around lateral malleolus of the fibula.

§  Ballistic inversion can cause “Jone’s fracture”: a piece of bone torn away from the peroneus brevis’s insertion point on base of 5^th metatarsal.

3.      Peroneus tertius (ANTEROlateral location)

§  Everts foot and dorsiflexes ankle.

§  Tendon doe NOT go around lateral malleolus of the fibular.

C.   Superficial Posterior Compartment

1.      Gastrocnemius                                                                     

§  Plantar flexes ankle and flexes knee.

§  A two-headed muscle (medial and lateral heads).

§   

2.      Plantaris                                                                   

§  Plantar flexes ankle and flexes knee.

§  The longest tendon of any muscle in the body.

3.      Soleus

§  Plantar flexes ankle.

§  Together these 3 muscles form a group called triceps surae.

§  A  insert on the calcaneal tendon (also called the Achilles tendon).

D.   Deep Posterior Compartment

1.   Tibialis posterior                                                                   

§  Plantar flexes ankle and inverts foot.

2.   Flexor digitorum longus

§  Plantar flexes ankle and inverts foot, and flexes MP, PIP, and DIP joints for the four lateral toes.

3.   Flexor hallucis longus

§  Plantar flexes ankle and inverts foot, and flexes MP and IP joints of the big toe.

 

 

 

 

 

 

 

 

 

 

 

 

 

KNEE

1. A synovial hinge (a modified hinge) joint formed by the articulation of the femur and tibia.

2. Complex ligament and muscular support also allows some rotation at the knee.

3. Patellofemoral joint: an articulation between the anterior surface of the distal end of the femur, between the lateral and medial condyles, is a smooth surface covered with articular cartilage known as the “patellar facet” and the posterior aspect of the patellar (kneecap). 

Supporting Ligaments:

A.  Patella Ligament

1.      Supports the front of the knee.

B.  Anterior Cruciate Ligament (ACL)

1. Prevents hyperextension of the knee joint (prevents the tibia from moving anterior to the femur).
2. Extends from the medial surface of the lateral condyle of the femur to the anterior and superior tibia.
3. ACL tears are very common (tends to occur when foot and tibia are planted and have ballistic knee extension or quick turn).
4. Cruciate means “cross.” 

C.  Posterior Cruciate Ligament (PCL)

1. Prevents movement of the femur anteriorly past the tibia.
2. Extends from the lateral surface of the medial condyle of the femur. to the posterior, superior tibia - criss crosses ACL.
3. PCL tears less common.

D.  Tibial collateral ligament (or Medial Collateral Ligament: MCL)

1. Provides medial support for knee joint.                                        
2. Tightens at full knee extension.
3. Extends from the medial condyle of the femur to the medial condyle of the tibia, also it attaches to the medial meniscus.

E.  Fibular collateral ligament (or Lateral Collateral Ligament: LCL)

1. Provides lateral support for knee joint.                                        
2. Tightens at full knee extension.
3. Extends from the lateral condyle of the femur to the head of the fibula – does Not attach to the lateral meniscus.

Other Supporting Tissues

A.  Menisci

1. A "C" shaped (medial meniscus) and “O” shaped (lateral meniscus) fibrocartilage pads that cover the surface of the superior tibia
• Absorb force between femur and tibia
• Cups femur - "sinks" the femur to center of the tibia surface by having wider outside surfaces.

2.  There is a medial meniscus and a lateral meniscus

• Held to one another by the transverse ligament.
• The medial meniscus is more extensive.
• Medial meniscus also injured more often because moves less within joint (because it is attached to the medial collateral ligament).

Muscles of the Knee

Hamstrings

·         Semimembranosus and Semitendinosus                                                                  Tendons of these muscles provide medial support to the knee joint.

·         Biceps femoris                                                                                                        Tendon provides lateral support to knee joint.

Flexors of the Knee: (other than the hamstrings)

·         Sartorius (flexes knee and laterally rotates thigh - as in sitting with knees crossed).

·         Popliteus (allows slight medial rotation that can unlock the knee from full extension).

·         Gastrocnemius (biarticulate - crosses knee and ankle).

·         Plantaris (also biarticulate).

Extensors of the Knee (quadriceps):

·         Rectus femoris (hip flexion, knee extension)

·         Vastus medialis

·         Vastus intermedius

·         Vastus lateralis

PELVIS AND HIP

1. Hip joint formed by head of the femur and acetabulum of the pelvis.                                          2. Stabilized by a pubofemoral, iliofemoral, and ischiofemoral ligaments.                                           3. Articular cartilage covers head of femur and acetabular surface (a synovial joint).         4. Aging dehydrates articular cartilage and may lead to arthritis.

Actions at Hip Joint

 A.  Flexion

1. Moving femur into the anterior plane (i.e., hip is flexed when seated)
2. Prime Movers

• Iliacus (hip flexion and external rotation)
• Psoas (iliacus + psoas sometimes referred to as iliopsoas).
•       Psoas Major (hip flexion and external rotation)
•       Psoas Minor (flexion of the pelvis and lumbar spine)
• Pectineus.
• Rectus femoris (biarticular, unlike other quadricep muscles).

B.  Extension

1. Moving femur into the posterior plane (i.e., extend hip when rising from seated position)

2. Prime Movers
• Gluteus maximus
• Contributes to extension from 45 degree flexion.
• Contributor to vertical jump.
• Biceps femoris (lateral femur).
• Semimembranosus (medial femur).
• Semitendinosus (medial femur).

             C.  Abduction

1.   Moving femur away from the midline.                                                                           2.   Prime mover

• Gluteus medius                                                                                

D.  Adduction

2. Moving femur toward the midline 
3. Prime movers
• Adductor magnus
• Adductor longus
• Adductor brevis
• Gracilis
• Pectineus

E.  Medial Rotation

1. Rotating anterior femur towards midline
2. Prime movers
• Gluteus minimus
• Tensor fasciae latae (also provides stability for knee)

F.  Lateral Rotation

1.   Rotating anterior femur away from the midline.                                            2.   Prime movers

• Piriformis
• Superior gemellus
• Internal obturator
• Inferior gemellus
• External obturator
• Quadratus femoris

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SHOULDER AND UPPER ARM

Refers to head of humerus, humerus, and glenoid fossa of scapula.  

Muscles that perform shoulder joint actions (most will have insertions on humerus). 

A. Rotator Cuff Muscles

1. Subscapularis
2. Supraspinatus
3. Teres minor
4. Inpraspinatus

a)      Lateral rotators

§  Infraspinatus and teres minor

§  Stop medial rotation at end of pitch (humerus rotating at 8000 degrees/sec)

§  Weakness in these muscles can cause injury because speed of humerus causes humerus head to rise in glenoid cavity (see abduction below)
 

b)       Abduction

§  Supraspinatus

§  Active during first 30 degrees of abduction, then deltoid takes over

§  Lies underneath acromion of scapula; if head of humerus rises in glenoid cavity can pinch supraspinatus against acromion, this condition is Rotator Cuff Impingement

§  Results in stretching and tearing of tendon; irritation                                                                                                     

c)       Medial rotation

§  Subscapularis

§  Only cuff muscle on anterior side of scapula (rest on posterior)

§  Only cuff muscle to insert on lesser tubercle (rest on greater tubercle)

B.  Prime Movers of Flexion

1. Anterior deltoid
2. Clavicular and sternal head of pectoralis major
3. Coracobrachialis

C.  Prime Movers of Extension

1. Sternal head of pectoralis major
2. Latissimus dorsi
3. Teres major

D.  Prime Movers of Abduction

1. Supraspinatus
2. Middle deltoid  
• Full abduction of humerus requires upward rotation of shoulder girdle in order to prevent impingement of humerus on acromion when humerus at 90 degrees

• Prime mover of upward rotation, serratus anterior

E.  Prime Movers of Adduction

1. Pectoralis major (sternal)
2. Latissimus dorsi
3. Teres major

F.  Prime Movers of Horizontal Flexion

1. Pectoralis major (both heads)
2. Anterior deltoid

G.  Prime Movers of Horizontal Extension

1. Middle, posterior deltoid

ELBOW, WRIST, & HAND

The forearm
 

A. Supported by two parallel, long bones

1. Radius: lateral bone (thumb side)
2. Ulna: medial bone (pinky finger side)

B. Three joints between the radius and ulna
 

3. 2 pivot joints - synovial joint classification
• Proximal radioulnar joint (at radial notch of ulna)
• Distal radiulnar joint (at ulnar notch of radius)
4. 1 syndesmosis - amphiarthrotic joint classification
• Interosseous membrane between the radius and ulna

C.  Supination and Pronation

1. Supination - movement of the distal end of the radius from a position, which crosses over the distal ulna to a position, which is parallel with the ulna.  (i.e., moving from "palms down" to "palms up")

                       a) Supinator muscles: Biceps brachii and Supinator

• Biceps assists Supinator during small movements
• Biceps becomes the prime mover with increasing resistance  

2.  Pronation - distal end of radius rotates around ulna; bones appear                         

                          crossed.

a)  Pronator muscles:  Pronator teres and Pronator quadratus

b)  Pronation affects the force, which elbow flexor muscles may                     

     develop

• Elbow flexors with insertions on the radius lose force when the forearm is pronated (rotation of radius causes a less direct line of pull)
• Biceps brachii (insertion = radial tuberosity of the radius) -- 40% less force developed during pronation

• Brachioradialis (insertion = styloid process of the radius) -- also a decrease in force
• Brachialis (insertion = ulnar tuberosity of the ulna) -- NO change in force

Elbow

1. Formed by articulation between the humerus and ulna and radius

2. A hinge joint - a synovial joint classification  

A.  Supporting ligaments

1.      Annular ligament - holds radius head to the ulna

2.      Ulnar ligament - holds ulna to the humerus

3.      Radial ligament - holds radius to the humerus

 Wrist

1. Formed by articulation between radius and carpal bones (scaphoid and lunate)

2. An ellipsoid joint - a synovial joint classification

A.  Supporting ligaments

1. Flexor retinaculum
• Connective tissue; forms a "wrist band" on the anterior side of the wrist
• Maintains the mechanical advantage of flexor muscles by preventing "bowing out" of flexor muscle tendons
2.  Extensor retinaculum - connective tissue; forms a "wrist band" on the posterior side of the wrist
• Maintains the mechanical advantage of extensor muscles by preventing "bowing out" of extensor muscle tendons
3. Palmar and dorsal radiocarpal ligaments
4. Transverse carpal ligament
• Median nerve lies beneath
• Overuse/flexion builds up the connective tissue and compresses median nerve resulting in Carpal Tunnel Syndrome

B.  Flexion and extension of the wrist  

5. Flexor muscles
• Origins typically on medial epicondyle of the humerus
• Flexor carpi radialis
• Palmaris longus
• Flexor carpi ulnaris
6. Extensor muscles
• Origins typically on lateral epicondyle of the humerus
• Extensor carpi radialis (longus and brevis)
• Extensor digitorum
• Extensor digiti minnimi
• Extensor carpi ulnaris

Hand
 

A. 8 carpal bones

1.      Form wrist

2.      Scaphoid, lunate, triquetral, pisiform, trapezium, trapezoid,capitate, hamate

B. 5 metacarpals

1. Form the palm of the hand             

2. Identified by number

• 1^st  metacarpal: located on thumb side
• 5^th metacarpal: located on pinky side

C. 14 phalanges

1. Form the digits

2. Phalanges in each of the 4 fingers - identified as proximal, intermediate, or           

   distal                   

• 2 phalanges in thumb - proximal and distal

      D. Digit flexors

      1. Flexor digitorum superficialis                 2. Flexor digitorum profundus