8. Anatomy | Functional Anatomy of the Upper Limb

What type of joint is the sternoclavicular (sternoclavicular) joint?

Synovial saddle

What bones are involved in the sternoclavicular (sternoclavicular) joint?

Sternum and clavicle

What movements are permitted at the sternoclavicular (sternoclavicular) joint?

Elevation, depression, protraction, retraction, axial rotation

What type of joint is the acromioclavicular (acromioclavicular) joint?

Synovial plane

What bones are involved in the acromioclavicular (acromioclavicular) joint?

Acromion and clavicle

What movements are permitted at the acromioclavicular (acromioclavicular) joint?

Gliding, rotation

What type of joint is the scapulothoracic joint?

Not a true joint (functional joint)

What bones are involved in the scapulothoracic joint?

Scapula and thoracic wall

What movements are permitted at the scapulothoracic joint?

Elevation, depression, protraction, retraction, upward/downward rotation

What type of joint is the glenohumeral joint?

Synovial ball and socket

What bones are involved in the glenohumeral joint?

Humeral head and glenoid fossa (scapula)

What movements are permitted at the glenohumeral joint?

Flexion, extension, abduction, adduction, internal/external rotation, circumduction

What type of joint is the humeroulnar joint?

Synovial hinge

What bones are involved in the humeroulnar joint?

Trochlea and trochlear notch (ulna)

What movements are permitted at the humeroulnar joint?

Flexion, extension

What type of joint is the humeroradial joint?

Synovial hinge/gliding

What bones are involved in the humeroradial joint?

Capitulum and radial head

What movements are permitted at the humeroradial joint?

Flexion, extension, assists with rotation

What type of joint is the proximal radioulnar joint?

Synovial pivot

What bones are involved in the proximal radioulnar joint?

Radial head and radial notch of ulna

What movements are permitted at the proximal radioulnar joint?

Pronation, supination

What type of joint is the distal radioulnar joint?

Synovial pivot

What bones are involved in the distal radioulnar joint?

Distal radius and ulna

What movements are permitted at the distal radioulnar joint?

Pronation, supination

What type of joint is the radiocarpal (wrist) joint?

Synovial condyloid

What bones are involved in the radiocarpal (wrist) joint?

Radius, scaphoid, lunate

What movements are permitted at the radiocarpal (wrist) joint?

Flexion, extension, radial/ulnar deviation, circumduction

What type of joint are the midcarpal and intercarpal joints?

Synovial plane

What bones are involved in the midcarpal and intercarpal joints?

Between carpal rows

What movements are permitted at the midcarpal and intercarpal joints?

Minor sliding/gliding

What type of joint is the carpometacarpal (carpometacarpal) joint of the thumb?

Synovial saddle

What bones are involved in the carpometacarpal joint of the thumb?

Trapezium and 1st metacarpal

What movements are permitted at the carpometacarpal joint of the thumb?

Flexion, extension, abduction, adduction, opposition

What type of joint are the carpometacarpal (carpometacarpal) joints of digits 2_5?

Synovial plane

What bones are involved in the carpometacarpal joints of digits 2_5?

Distal carpals and metacarpals

What movements are permitted at the carpometacarpal joints of digits 2_5?

Minimal movement (5th has slight opposition)

What type of joint are the metacarpophalangeal (metacarpophalangeal) joints?

Synovial condyloid

What bones are involved in the metacarpophalangeal joints?

Metacarpals and proximal phalanges

What movements are permitted at the metacarpophalangeal joints?

Flexion, extension, abduction, adduction

What type of joint are the proximal interphalangeal (proximal interphalangeal) joints?

Synovial hinge

What bones are involved in the proximal interphalangeal joints?

Proximal and intermediate phalanges

What movements are permitted at the proximal interphalangeal joints?

Flexion, extension

What type of joint are the distal interphalangeal (distal interphalangeal) joints?

Synovial hinge

What bones are involved in the distal interphalangeal joints?

Intermediate and distal phalanges

What movements are permitted at the distal interphalangeal joints?

Flexion, extension

What type of joint is the thumb interphalangeal joint?

Synovial hinge

What bones are involved in the thumb interphalangeal joint?

Proximal and distal phalanges

What movements are permitted at the thumb interphalangeal joint?

Flexion, extension

What muscles are associated with the sternoclavicular and acromioclavicular joints?

Trapezius, sternocleidomastoid, deltoid

What ligaments stabilize the sternoclavicular and acromioclavicular joints?

Sternoclavicular, costoclavicular, interclavicular, acromioclavicular, coracoclavicular (trapezoid and conoid)

What muscles are associated with the scapulothoracic joint?

Serratus anterior, trapezius, rhomboids, levator scapulae

What stabilizes the scapulothoracic joint?

Muscle tension (not a true joint)

What muscles are associated with the glenohumeral joint?

Deltoid, pectoralis major, latissimus dorsi, teres major, rotator cuff muscles (supraspinatus, infraspinatus, teres minor, subscapularis)

What ligaments stabilize the glenohumeral joint?

Glenohumeral ligaments (superior, middle, inferior), coracohumeral ligament, rotator cuff tendons reinforce capsule

What is the mnemonic for the rotator cuff muscles and their actions?

SITS: - Supraspinatus: Abduction (first 15º); - Infraspinatus: External rotation; - Teres minor: External rotation;- Subscapularis: Internal rotation

What muscles are associated with the humeroulnar joint?

Brachialis (flexion), triceps (extension)

What ligament stabilizes the humeroulnar joint?

Ulnar Collateral Ligament (UCL) / Medial Collateral Ligament → resists valgus stress

What muscles are associated with the humeroradial joint?

Biceps brachii (flexion, supination), brachioradialis

What ligament stabilizes the humeroradial joint?

Radial Collateral Ligament (RCL) / Lateral Collateral Ligament

What muscles act at the proximal/distal radioulnar joints?

Pronator teres, pronator quadratus (pronation); supinator, biceps brachii (supination)

What ligament stabilizes the proximal radioulnar joint?

Annular ligament → encircles radial head for spinning motion

What muscles act at the radiocarpal (wrist) joint?

Flexor carpi radialis/ulnaris, extensor carpi radialis/ulnaris, palmaris longus

What ligaments stabilize the radiocarpal (wrist) joint?

Radial and ulnar collateral ligaments, palmar radiocarpal, dorsal radiocarpal ligaments

What muscles act at the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints?

Flexors: flexor digitorum superficialis (proximal interphalangeal), flexor digitorum profundus (distal interphalangeal); Extensors: extensor digitorum; Intrinsics: lumbricals, interossei

What ligaments stabilize the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints?

Collateral ligaments, volar plate

What muscles act at the thumb carpometacarpal joint?

Thenar muscles: opponens pollicis, abductor pollicis brevis, flexor pollicis brevis

What ligament stabilizes the thumb carpometacarpal joint?

Anterior oblique ligament (key stabilizer)

What innervates the palmar and dorsal interossei muscles?

Ulnar nerve

Where do the lumbricals arise from?

Tendons of flexor digitorum profundus

What actions are produced by lumbricals and interossei?

Flex MCP joints, extend PIP and DIP joints

What is the mnemonic PAD/DAB used for?

PAD = Palmar ADduct, DAB = Dorsal ABduct

What is the mechanism of anterior shoulder dislocation?

Arm in abduction, extension, and external rotation; glenohumeral head dislocates anteroinferiorly

What are key findings in anterior shoulder dislocation?

Flattened shoulder, prominent acromion, humeral head displaced on imaging

What is the mechanism of Nursemaid's elbow?

Radial head subluxation from annular ligament due to traction (e.g., pulling child's arm)

What are key findings in Nursemaid's elbow?

Pain at lateral elbow, refusal to use arm

What causes Mallet Finger?

Terminal extensor tendon rupture at DIP joint

What are the findings in Mallet Finger?

Flexed DIP that cannot actively extend

What causes Boutonniere's Deformity?

Central slip rupture, lateral bands slide volarly

What are the findings in Boutonniere's Deformity?

PIP flexion, DIP extension (Buttonhole posture)

What causes Swan Neck Deformity?

Rheumatoid arthritis or tendon imbalance, hyperextension at PIP, flexion at DIP

What are the findings in Swan Neck Deformity?

PIP hyperextension, DIP flexion (Swan posture)

What is the mnemonic to remember finger deformities?

"Mallet = DIP stays Down

Boutonnire = Buttonhole at PIP

Swan = Swooping PIP extension, DIP flexion"

What condition is shown and what are the effects?

PIP flexion, DIP and MCP extension (Boutonnière)

What condition is shown and what are the effects?

DIP flexion (Mallet finger)

Where does extensor digitorum originate and insert?

"Origin: Posterior forearm

Inserts into extensor expansion"

What condition is shown and what are the effects?

What joints are extended by extensor digitorum?

MCP, PIP, and DIP joints

What is the extensor expansion (hood)?

Aponeurotic structure over dorsal digits where ED, lumbricals, interossei insert

What is the central band in the extensor expansion and its insertion?

Continuation of ED inserting on intermediate phalanx

What are the lateral bands and their insertion?

Split from ED, merge as terminal tendon to insert on distal phalanx

What is the terminal tendon and where does it insert?

Formed by lateral bands; inserts on distal phalanx

What is the function of the extensor expansion?

Allows simultaneous extension at MCP, PIP, and DIP joints

What is the role of lumbricals and interossei in the extensor mechanism?

Flex MCP, extend PIP and DIP via lateral bands

What motion is impaired with supraspinatus injury?

Difficulty initiating arm abduction

What motion is impaired with subscapularis injury?

Loss of internal (medial) rotation

What happens with annular ligament injury in a child?

Radial head dislocation; impaired pronation/supination

What deformity results from central slip rupture?

Boutonnière deformity → PIP flexion, DIP extension

What deformity results from terminal tendon rupture?

Mallet finger → DIP flexion

What is the effect of ulnar nerve injury affecting lumbricals/interossei?

MCP extension with PIP/DIP flexion → claw hand (esp. digits 4→5)

Where is the flexor digitorum superficialis located in the forearm?

It is the more superficial muscle in the anterior compartment of the forearm.