The hand and joints of the upper limb Flashcards
How are carpal bones connected to each other?
Intercarpal ligaments
What are the components of each metacarpal bones?
Base, shaft and head
How much movement at the carpometacarpal joint?
Minimal movement, except at thumb where more movement is permitted
What type of joint is the first (thumb) carpometacarpal joint?
Saddle-shaped
What joins the shafts of the metacarpal bones?
Transverse metacarpal ligaments and the palmar and dorsal interossei
What is the shape of the metacarpophalangeal joints?
Condyloid (shaped like knob and cup)
What type of movement is enabled by condyloid joints?
Biaxial (movement in 2 planes)
What are the components of the phalangeal bones?
How many phalanges are there in each digit?
Base, shaft and head
3 in fingers (proximal, middle, distal)
2 in thumb (proximal and distal)
What is the classification of the interphalangeal joints?
Hinge joints
What movement is permitted by the interphalangeal joints?
Flexion and extension
What stabilises the interphalangeal joints?
Radial and ulnar collateral ligaments
What is the classification of the elbow joint?
Synovial hinge joint
What happens to the radial head during pronation/supination at the elbow joint?
Articulates with the ulna
What happens to the radial head during flexion/extension at the elbow joint?
Slides onto the capitulum of the humerus
Where does the capsule of the elbow joint attach?
The margins of the articular surfaces
The epicondyles are extracapsular
Where is the capsule of the elbow joint lax?
Why is this?
Anteriorly and posteriorly
To permit full flexion and extension
How is stability of the elbow joint maintained?
The congruous articular surfaces of the trochlea and trochlea fossa
Medial and lateral collateral ligaments
Anular ligament around the radial neck
What joints are involved in pronation/supination?
Superior and inferior radio-ulnar joints
The superior RU joint communicates with the elbow joint
What is the classification of the wrist joint?
Synovial ellipsoid joint
What bones are connected by the wrist joint?
Concave distal surface of the radius articulates with the convex proximal surfaces of the scaphoid and lunate
How is the head of the ulna separated from the triquetrial bone?
How is the wrist joint separated from the distal radio-ulnar joint?
a triangular fibrocartilaginous disc which attaches to the edge of the ulnar notch of the radius and the base of the styloid process of the ulna
What is the function of palmaris brevis?
Improves grip by stabilising the skin on the ulnar side of the palm
Where is palmaris brevis?
Attached to the dermis and lies across the base of the hypothenar eminence
What is the palmar aponeurosis?
Deep fascia of the palm to which the skin is firmly attached
(skin around palmaris brevis is an exception)
Why do large subcutaneous veins drain from the palm?
So that the pressure of gripping does not impede venous return
Describe the structure of the palmar aponeurosis
Consists of a central part that is thick and unyielding. Thinner over the thenar and hypothenar eminences for increased mobility
What is proximal to the palmar aponeurosis?
Tendon of palmaris longus
What is distal to the palmar aponeurosis?
Divides into 4 sheaths which are continuous with the fibrous flexor sheaths for the fingers
What are the muscles of the thenar eminence?
Abductor pollicis brevis (lateral), flexor pollicis brevis(medial), opponens pollicis (deep)
What are the muscles of the hypothenar eminence?
Abductor digiti minimi (medial), flexor digiti minimi (lateral) and opponens digiti minimi
Which nerve supplies the thenar eminence?
Recurrent branch of the medial nerve
Which nerve supplies the hypothenar eminence?
The ulnar nerve
What are the deep muscles of the hand?
Adductor pollicis, interossei and lumbricals
Which nerve supplies the deep muscles of the hand?
Ulnar nerve, except of lateral 2 lumbricals (median)
How many palmar interossei are there?
3
How many dorsal interossei are there?
4
Where do the interossei originate?
The shafts of the metacarpals
Where do the interossei insert?
Proximal phalanges
What is the function of the palmar interossei?
Adduction (PAD)
What is the function of the dorsal interossei?
Abduction (DAB)
How many metacarpals does each palmar interossei arise from?
1
How many metacarpals does each dorsal interossei arise from?
2
How many lumbricals are there?
4
Where do the lumbricals originate?
The tendons of the FDP
Where do the tendons of the FDP insert?
Passes around the radial aspect of each finger to insert onto the dorsal expansion
What is the function of the lumbricals?
Acts with the interossei to flex the metacarpophalangeal joints and extend the interphalangeal joints
Which nerve supplies the lumbricals?
Medial 2 = ulnar
Radial 2 = median
What is the blood supply of the hand?
Superficial and deep palmar arches
What is the superficial palmar arch a continuation of and where does it enter the palm?
Continuation of ulnar artery
Enters palm with ulnar nerve, superficial to the flexor retinaculum
What is the deep palmar arch a continuation of and where does it enter the palm?
Continuation of the radial artery
Passes between the first dorsal interosseous and adductor pollicis to enter the palm from its dorsal aspect
