Upper & Lower Extremities

Learning Objectives

1. Name & identify the key bones (and bony features) of the upper & lower extremities? 2. Name & describe the major joints of the upper & lower extremities? Identify their functions and supporting structures? 3. Name & identify the main muscles of the upper & lower extremities and describe their functions? THE SHOULDER – Rules of 3 • Comprised of: – 3 bones – 3 joints – 3 groups of muscles • Represents only attachment of appendicular skeleton (arm) to axial skeleton (trunk).

1. Clavicle

• "S" shaped bone that acts like a strut (keeps shoulders back and arms at side) • Length of clavicle = broadness of shoulders • Medial one third is convex anteriorly (rounded outward) • Lateral one third is concave anteriorly (curved inward) • Functions in force absorption (Foosh), dissipation of force, & rotation of the scapula in abduction

2. Scapula

• 'spade‘ shaped • thin , flat, triangular with 3 borders • NO attachment to chest wall • held against ribs by muscles

3. Humerus:

• typical long bone (shaft and 2 enlarged ends) • proximal end (head of humerus) • articulates with the glenoid fossa of scapula

1. Sternoclavicular joint

• Formed by medial clavicle and clavicular notch of the Sternum • Synovial joint • Saddle type joint • Subtle movements occur about a multi axial plane.

2. Acromioclavicular joint

 Palpable, rounded eminence on lateral shoulder or "Point of the shoulder“  Lateral clavicle articulates with acromion process (spine of scapula).  Plane type synovial joint  Supported by thick ligaments  Allows for rotational movements of clavicle on acromion  Injury of joint referred to as “shoulder separation" 3. Shoulder (Gleno – humeral) Joint

• Articulation between head of humerus and glenoid of the scapula • Multi-axial, ball & socket type synovial joint • Freely movable, but structurally unstable because very little of humeral head (1/3rd) is in contact with fossa at any one time. • Glenoid is deepened by a cartilaginous ring (labrum), and stabilized by strong ligaments

G-H Joint 3 sets of Movements

1. Flexion / Extension 2. Abduction / Adduction 3. Medial / Lateral Rotation

Scapulo-Humeral Motion • Movement of the scapula relative to movement of the humerus • 1° of scapular movement for every 2° of GH movement • 180° degrees of shoulder abduction: – 120° from GH joint – 60° from ST articulation • Scapular movement requires movement of the clavicle 3 Other Paired Movements of the Shoulder Girdle (require movements at all 3 joints) 1. Elevation / Depression 2. Protraction / Retraction 3. Cross flexion / Extension 3 Main Groups of Shoulder Muscles

Posterior Muscles

Anterior Muscles 1. THORAX TO HUMERUS:

1. LATISSIMUS DORSI 2. PECTORALIS MAJOR Pectoralis Major

• GD: Large, superficial muscle of chest that forms the anterior wall of axilla • Functions to power shoulder flexion, adduction and medial rotation (ie. 'bear hug“).

Latissimus Dorsi

 GD: Large, superficial, broad muscle of back; Diamond shaped  Forms posterior wall of axilla(armpit)  Arises from lower back and inserts prox. humerus  Functions: • Shoulder extension • Adduction • Medial rotation • Composite action: swimming, paddling

2. THORAX TO SCAPULA/CLAVICLE

1. TRAPEZIUS 2. RHOMBOID MAJOR & MINOR 3. PECTORALIS MINOR

Trapezius:

• GD: Large, superficial, triangular muscle of the upper back and neck region. • Large number of functions, depending on location & direction: 1. Upper fibers: • scapular elevation/rotation ("shrug“) • Neck Side Flexion (unilateral) or Extension (bilateral) 2. Middle fibers: • scapular retraction 3. Lower fibers: • pull medial end of scapular spine down. • (rotates glenoid fossa upward) • important to facilitate raising the arm over head Rhomboid Major & Minor

 Deep to trapezius  Functions to retract scapula Pectoralis Minor: • Positioned deep to pectoralis major muscle • Functionally very different from pectoralis major. • Functions: protraction of scapula (powers reach beyond reach) 3. SCAPULA / CLAVICLE TO HUMERUS:

1. DELTOID 2. ROTATOR CUFF (SITS) MUSCLES: – SUPRASPINATUS, – INFRASPINATUS – TERES MINOR – SUBSCAPULARIS Deltoid • Round muscle on top of shoulder, provides bulk of shoulder. • forms "U" around the shoulder -3 distinct heads: – Anterior: shoulder flexion – Middle: shoulder abduction – Posterior: shoulder extension Rotator Cuff • Intrinsic muscles of shoulder • Comprised of four separate muscles (SITS) to originate from scapula to attach to head of the humerus 1. Supraspinatus – Abduction of shoulder 2. Infraspinatus - Lateral rotation of shoulder 3. Teres minor - Lateral rotation of shoulder 4. Subscapularis - Medial rotation of shoulder Supraspinatus

• Action: – abduction of the shoulder (esp. first 150) Infraspinatus

Action: Lateral rotation Teres Minor

Action: Lateral rotation Subscapularis

GD: Located on front side of the scapula Action: Medial rotation

Biceps Region

 Superficial muscles on the anterior surface of the upper arm

 3 MUSCLES • Coracobrachialis • Biceps brachii • Brachialis

Function:  ELBOW FLEXION  FOREARM SUPINATION

Triceps Region

 3 HEADED MUSCLE ON POSTERIOR ARM (BRACHIUM)  TRICEPS BRACHII  ALL INVOLVED IN POWERING ELBOW EXTENSION ALL

Elbow & Forearm

Ulna  Little finger (ulnar) side  Part of the elbow joint “proper”.  Proximal end is shaped like a wrench (Olecranon Process)  Distal "head" is small and terminates as the ulnar styloid process medially.  Does not contact the carpal bones of the wrist directly (disc seperates them). Radius • Thumb (radial) side of the forearm • Articulates directly with the wrist. • The proximal end is a small rounded "head“ • Distal end is larger and ends as the radial styloid process laterally.

ELBOW JOINT • Hinge type, synovial that allows flexion / extension  During flexion trochlear notch of ulna aritulcates with the trochlear surface of the humerus  The radial head glides on the capitulum Proximal Radioulnar Joint:

• Joint between proximal radius and ulna • Pivot joint • Radius and ulna are always side by side proximally • They cross each other distally in pronation • allows for pronation/supination

MUSCLES OF THE FOREARM Think in terms of “pairs” • Posterior • Anterior MUSCLES OF THE FOREARM Think in terms of “pairs” 1. ANTERIOR vs POSTERIOR 2. MEDIAL vs. LATERAL EPICONDYLE 3. FLEXION vs EXTENSION 4. PRONATION vs SUPINATION

- Each compartment contains superficial and deep muscles. - All forearm muscles are termed as “extrinsic muscles” of the hand. - Involved in powering movements of the wrist, thumb and fingers

Movements

ANTERIOR POSTERIOR • FLEXION (wrist & fingers) • EXTENSION (wrist & fingers)

• ULNAR DEVIATION • ULNAR DEVIATION (adduction) (adduction)

• RADIAL DEVIATION (abduction) • RADIAL DEVIATION (abduction) SUPINATION •

• WRIST PRONATION THUMB EXTENSION •

• THUMB FLEXION • THUMB ABDUCTION

Anterior Compartment Superficial Layer  5 Muscles: 1. Pronator Teres 2. Flexor Carpi Radialis 3. Palmaris Longus 4. Flexor Carpi Ulnaris* 5. Flexor Digitorum Superficialis

Anterior Compartment Deep Layer • 3 Muscles: 1. Flexor digitorum profundus*

2. Flexor pollicis longus

3. Pronator quadratus

Posterior Compartment Superficial Layer • 5 Muscles: 1. Extensor Carpi Radialis Longus 2. Extensor Carpi Radialis Brevis 3. Extensor Digitorum 4. Extensor Digiti Minimi 5. Extensior Carpi Ulnaris

Posterior Compartment - Deep Layer

• 5 Muscles: 1. Supinator 2. Abductor Pollicis Longus 3. Extensor Pollicis Longus 4. Extensor Pollicis Brevis 5. Extensor Indicis

Wrist & Hand “SMALL BUT POWERFULL” 1. Carpal Bones

• There are 8 short bones arranged in two rows in the proximal aspect of the hand • They allow for mobility of the hand and opposition which is unique to the human species • Proximal row from lateral to medial: Scaphoid, Lunate, Triquetrum and Pisiform • Distal row from lateral to medial: Trapezium, Trapezoid, Capitate and Hamate

• She Likes To Play Try To Catch Her

2. Metacarpels

• 5 metacarpals that make up the palm of the hand. • Numbered 1 to 5 beginning with the thumb…the 5th metacarpal is on the ulnar side of the hand. • Consist of a proximal base, shaft and distal head

3. Phalanges • Fingers of the hand • The thumb has two phalanges (proximal and distal) • The remaining 4 digits are made up of three phalanges each (proximal, middle and distal) Wrist and Hand

 The wrist joint is comprised of the distal end of the radius and the proximal row of bones in the hands ( carpal bones).  The ulna is separated from the carpals by a fibro-cartilagenous disc and does not contribute to the wrist joint.  Condyloid, synovial joint because of the shape of the radius and the two carpal bones the radius directly articulates with (scaphoid and lunate)

Thumb (1St CMC) • Saddle type synovial joint between the trapezium and the base of the first metacarpal. • Allows for opposition! • Movements include Flex/ext, abd/adduction, & opposition (which is really a limited type of rotation)

Metacarpel-phalangeal Joints (MCPs)

• Heads of metacarpels contributes to the knuckle of the hand..otherwise known as the Metacarpalphalangeal joint…or MCP joints • The MCP’s allow for flexion/extension, abduction/adduction, with middle finder used as the point of reference to describe abduction and adduction

Interphalangeal Joints (IP’s)

1. Proximal Interphalangeal (PIP) joint 2. Distal Interphalangeal (DIP) joint (digits 2-5) • Interphalangeal joints are hinge joints and allow flexion / extension Muscles of the Hand - Rule of 3’s: • 3 Compartments – THENAR (3) – HYPOTHENAR (3) – Central (3) • 3 Movements

• All are intrinsic muscles of the hand. • Precision movements, fine motor skills Thenar Muscles  Is the fleshy prominence on the radial (thumb) side of the palm.  Comprised of 3 muscles that act on the thumb. 1. Opponens pollicis 2. Abductor pollicis brevis 3. Flexor pollicis brevis Hypothaner Muscles • Is the fleshy prominence on the lateral side of hand (ball of the little finger) • Comprised of 3 Muscles 1. Opponens digiti minimi 2. Abductor digiti minimi 3. Flexor digiti minimi brevis Central Compartment

 Muscles between hypo and thenar eminences.  Muscles more prominent on palmer surface.  Comprised of 3 Muscle groups: 1. Inter-ossei (4 dorsal / 3 palmer) A: abd / adduction of MCP joints

2. Lumbricals (4) A: Flex MCP joints with straight fingers

3. Adductor pollicis A: Adduct thumb

Lower Extremity Functions • Responsible for stability (posture) and locomotion. • Works concentrically: – Jumping (hip extension) – Climbing stairs (hip extension) – Rising from sitting to standing (hip extension) – Skating (hip abduction/extension/lat. rotation) • Muscles of the lower limb have an anti-gravity function…..ie. they Work eccentrically: – Descending stairs – Lowering from standing to sitting Pelvic region = between iliac crest and gluteal fold

Thigh = between hip and knee

Lower Leg = Region below the knee

Pelvic Girdle:

• Pelvis: basin (Latin) • Strong , stable joint • Weight bearing • Bones firmly united to form a basin • Structured for bipedal movement (upright walking) • Bones form a complete ring virtually immovable Innominate (hip)Bone • Comprised of three bones that eventually fuse together.

1. Ilium – The large fan shaped bone that makes up the proximal portion of the innominate bone – protects lower abdominal contents – provides surface area for attachment of large powerful muscles 2. Ischium – The bone that makes the posterior and inferior aspect of the innominate bone

3. Pubis – Makes up the anterior/inferior aspect of the innominate bone

Innominate Fusion

• Note: the fusion of the three bones is best observed as "Y" shaped markings inside the socket of the hip joint (Acetabulum) Anterior View Head Neck Greater trochanter

Lesser trochanter

Intertrochanteric line Joints of Sacroiliac Pelvic Girdle SACROILIAC JOINT

• The joint between the auricular surface of the ilium and the auricular surface of the sacrum.

• The SI joint is partly synovial (anterior) and partly fibrous (posterior).

• Allows for some flexion/extension • Important in walking and in full forward flexion.

• Supported by very strong anterior and posterior SACROILIAC LIGAMENTS .

Symphysis Pubis:

• Is the point where the two pubic bodies join anteriorly. • Joined by two very strong ligaments superior and inferiorly • Has a dense fibrocartilagenous disc in between which allows minimal movement • Softens and loosens in late pregnancy

THE HIP JOINT THE HIP JOINT:

• Best example of ball and socket joint.

• Articulation between the head of the femur and the acetabulum of the innominate bone

• It is one of the most secure, yet very mobile joints

• It is a synovial and multi- axial joint

ACETABULUM: • Is an incomplete ring on the lateral surface of the innominate bone • Closed in by the transverse acetabular ligament • ACETABULAR FOSSA – Deepest part of the acetabulum – Does not articulate with the femur – LUNATE SURFACE: • Horseshoe shaped articular (hyaline) cartilage • articulates with the head of the femur Hip Movements

1. Flexion /Extension 2. Abduction / Adduction 3. Internal / External Rotation

GLUTEUS MAXIMUS

• Largest muscle of gluteal region

• Function: – POWERFUL EXTENSOR OF HIP

– LATERAL ROTATION OF THE EXTENDED HIP

– COMPOSITE MOTION: PUSH-OFF IN SKATING

GLUTEUS MEDIUS & MINIMUS • Critical stabilizer of pelvis during single leg support such as walking & running • Maintains horizontal pelvic alignment during single leg stance phase •Inability to stabilize results in “waddling” or Trendenlenburg gait pattern. Function: – INTERNAL HIP ROTATION – ABDUCTION OF HIP

Piriformis Muscle (deep gluteal muscle) • Works in conjunctions with 5 small muscles collectively referred to as the “lateral rotators”. • Analogous to the rotator cuff of the upper extremity.

1. SUPERIOR GEMELLUS 2. INFERIOR GEMELLUS 3. QUADRATUS FEMORIS 4. OBTURATOR INTERNUS 5. OBTURATOR EXTERNUS

Anterior Hip – Ilio Psoas

This muscle is 2 separate muscles at its proximal end, the psoas major and iliacus, which join distally and have a common attachment on the femur. Function: Flexion of thigh / hip joint Medial Thigh – “Groin” region

• 5 MUSCLES • ALL CROSS THE HIP JOINT • ONLY ONE--CROSSES THE KNEE - GRACILUS • COMMON FUNCTION IS HIP ADDUCTION

The Thigh & Knee Region Anterior Thigh

• Large……Powerful…..Anti- gravity muscles

• Essential for activities of daily living: – Walking, running, jumping – Sit up/down, up/down stairs – Sporting activities

• Circulation via femoral artery & vein N: All by femoral nerve (L2 – L4)

QUADRICEPS FEMORIS

MUSCLE • 4 DISTINCT PARTS

• Rectus Femoris: Straight superficial portion that crosses both hip and knee joints • Power hip flexion / knee extension

• The Vasti - medialis/intermedius/lateralis They surround that shaft of femur and wrap around thigh from back. • Power only knee extension

Quadriceps Tendon

Patella Tendon/Ligament

POSTERIOR THIGH - “HAMSTRINGS”

• GD: 3 MUSCLES, ALL 2-JOINT

• CROSS BOTH HIP AND KNEE

Knee flexion Hip Extension • Anatomical Overview Bones: - Femur - Patella - Tibia - Fibula

*NOTE: fibula is non weightbearing / non articulating in the knee joint

Patella

• Patella – sesamoid bone

• 1st appears about 7.5 weeks of gestation

• Shaped like a triangle, being slightly wider than high

• Constant in both width & height

• Medial border is thicker than lateral

• Large variability in thickness of bone & articular cartilage Patellofemoral Joint (PFJ)

• Articulation between the trochlea of the femur and the posterior surface of the patella.

• Considered the Centerpiece of the extensor mechanism.

• Common site of dysfunction

• Structure – well defined!

• Function – many variables!!! Anatomy of the Tibio / Femoral Joint “The Knee Joint” • Synovial (MODIFIED hinge) joint that allows flexion/extension and some rotation • Largest and most complex joint in the human body • Lacks bony stability • Movements – Flexion / extension (approx. 135 degrees) – Medial / lateral rotation • Only occurs when knee is flexed. • Max’s out at approx. 45 degrees when knee flexed to 90 degrees. MEDIAL COLLATERAL LIGAMANT “MCL” Fan shaped Attaches to the medial femoral epicondyle proximally and medial surface of the tibia distally Also attached to the medial meniscus Resists valgus force LATERAL COLLATERAL LIGAMENT “LCL”  Cord like ( nearer to back of joint)  From lateral epicondyle of the femur to fibular head  Easily palpated (can roll with finger)  Resists varus force Cruciate Ligaments

• Anatomically: – Anterior Cruciate Ligament (ACL) – Posterior Cruciate Ligament (PCL) – Inadequate ability to heal after injury • Functionally: – 1° restraint – tibial translation (TT) – 2 ° restraint – int / ext rotation of tibia on femur. Meniscus

Medial: – C shaped, attached to joint capsule and medial collateral ligament (MCL) Lateral: – O shaped, connected to popliteus muscle Functions: 1. Deepen the tibial surface to increase joint stability. 2. Spreads out the load bearing force on the joint. 3. Helps in the control of rotational and gliding motion at the tibio-femoral joint. 4. Helps circulate the synovial fluid thru the joint. Lower leg, Ankle & Foot Tibia/Fibula BONES OF THE FOOT

• Analogous to the bones of the hand but modified for weight bearing and locomotion. • 7 Tarsal bones

• 5 Metatarsals

• 14 Phalanges ANKLE JOINT The ankle joint is a synovial joint comprised of two articulations. 1. Talocrural (true) Ankle joint 2. Subtalar Joint

– Stable in dorsi flexion / Unstable in planter flexion – Strong ligaments / weak muscles

TALOCRURAL JOINT • True Ankle Joint • Between the distal end of the leg bones (tibia and fibula) and the talus. • Referred to as a brick and mortar joint because of its bony configuration • The tibia and fibula form a mortise in which the dome of the talus fits. • More stable with eversion then Inversion!

Ankle Movements

Talocrural Joint: • Dorsiflexion • Plantarflexion

SUBTALAR JOINT

• The joint between the superior aspect of the calcaneus and the inferior aspect of the talus.

Ankle Movements

Subtalar joint: • Eversion • inversion MUSCULAR COMPARTMENTS OF THE LOWER LEG

• Three compartments – Anterior • Dorsiflexors/Toe Extensors – Lateral • Everters – Posterior • Plantarflexors/Toe flexion – No Medial compartment Anterior Compartment • 3 MUSCLES 1. Tibialis anterior 2. Extensor Hallucis longus 3. Extensor Digitorum longus

Lateral Compartment

• 2 MUSCLES – All wrap around lateral malleolus – ankle eversion – Support lateral longitudinal arch Posterior Compartment (superficial)

• 3 MUSCLES – Common distal attachment: Achilles tendon

Posterior Compartment (deep) - TDH

• 3 MUSCLES – T / D / H – All wrap around medial malleolus – Insert into foot, support medial longitudinal arch ARCHES OF THE FOOT • There are three arches to the foot 1. Medial Longitudinal 2. Lateral Longitudinal 3. Transverse/Metatarsal • Combination of dynamic muscle and static ligamentous support • Pes planus / Pes cavus

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