PALM
Palmar aponeurosis (LE)/ (SE)
Palmar aponeurosis is the deep fascia in the central region of the palm. It is regarded as the degenerated tendon of palmaris longus.
Features
It is Triangular in shape and has
Apex, Base, Medial border and Lateral border
Apex
Is the narrow proximal end.
It blends with flexor retinaculum.
Base
is the broad distal end
divides into four longitudinal slips proximal to heads of metacarpals to medial four digits
each slip further divides into two slips which blend with fibrous flexor sheath of corresponding digits.
The digital nerves, vessels and tendon of lumbricals emerge through the interval between four longitudinal slips
Medial border
Continuous with deep fascia covering the hypothenar muscles
Gives origin to palmaris brevis
Lateral border
Continuous with deep fascia covering the thenar muscles
From the medial and lateral borders, medial and lateral palmar septa pass backwards and divide the palm into compartments.
Functions:
Helps to improve the grip of hand by fixing the skin
Protects the underlying tendons, nerves and vessels
ADDUCTOR POLLICIS MUSCLE (SE)
Adductor pollicis is a fan shaped muscle located deep in the palm.
Origin
Consists of two heads (a) oblique (b) transverse
Oblique head : base of 2nd and 3rd metacarpal
Transverse head: shaft of 3rd metacarpal
Insertion:
Base of proximal phalanx of thumb
Nerve supply:
Deep branch of ulnar nerve( C8, T1)
Action:
Adduction of the thumb
Lumbricals – attachments , nerve supply and actions (SE)/ Nerve supply and actions (SA)
Lumbricals are four small,
Origin
All arise from 4 tendons of flexor digitorum profundus. Lumbricals 1 and 2 (unipennate)
From lateral side of lateral two tendons of flexor digitorum profundus Lumbricals 3 and 4 (bipennate)
From adjacent sides of medial three tendons of flexor digitorum profundus
Insertion
To lateral side of dorsal digital expansion of 2nd to 5th digits
Nerve supply
1st and 2nd lumbricals – median nerve
3rd and 4th lumbricals- deep branch of ulnar nerve
Actions
Flexion at metacarpophalangeal joints
Extension at proximal and distal interphalangeal joints
PALMAR APONEUROSIS (SA)
It is central part of the deep fascia of the palm and degenerated tendon of palmaris longus.
Features
It is triangular in shape
It has Apex, Base, Medial border,& Lateral border
Apex
Is the narrow proximal end.
It blends with flexor retinaculum.
Base
Is the broad distal end
Divides into four longitudinal slips to medial four digits
Each slip further divides into two slips which blend with fibrous flexor sheath of corresponding digits.
The digital nerves, vessels and tendon of lumbricals emerge through the interval between four longitudinal slips
Medial border
Continuous with deep fascia covering the hypothenar muscles Gives origin to palmaris brevis
Lateral border
Continuous with deep fascia covering the thenar muscles
Functions
(1)Helps to improve the grip of hand by fixing the skin
(2)Protects the underlying tendons, nerves and vessels
ADDUCTOR POLLICIS (SA) Origin:
Oblique head : base of 2nd and 3rd metacarpal
Transverse head: shaft of 3rd metacarpal
Insertion:
Base of proximal phalanx of thumb
Nerve supply
Deep branch of ulnar nerve ( C8, T1)
Actions
Adduction of the thumb
MUSCLES OF HYPOTHENAR EMINENCE (SA)
(a)abductor digiti minimi
(b)flexor digiti minimi
(c)opponens digiti minimi
Supplied by deep branch of ulnar nerve.
NERVE SUPPLY OF DORSAL INTEROSSEI OF HAND (SA)
All the four dorsal interossei are supplied by deep branch of ulnar nerve.
ACTIONS OF INTEROSSEI OF HAND (SA)
Palmar interossei:
Adduct fingers towards centre of middle finger
Dorsal interossei:
Abduct fingers from centre of third digit.
Both palmar and dorsal interossei flex the matacarpophalangeal joints and extend the interphalangeal joints.
DUPUYTREN’S CONTRACTURE (SA)
It is a condition in which there is fixed forward curvature of one or more fingers,
Cause
Progressive fibrosis in the medial part of palmar aponeurosis
Results in permanent contraction
Causing fixed flexion deformity of liitle and ring fingers
Proximal and middle phalanges are acutely flexed but distal phalanges remain unaffected.
POSTERIOR COMPARTMENT OF FOREARM
SUPINATOR MUSCLE (SE)
Supinator is a deep muscle of forearm.
Origin
Lateral epicondyle of humerus
Lateral ligament of elbow joint
Annular ligament
Supinator crest of ulna.
Insertion
Upper 1/3rd of posterior , lateral and anterior surface of radius.
Nerve supply
Posterior interosseous nerve – branch of radial nerve.
Action
Supination of forearm.
Posterior interosseus nerve (SE)
Posterior interosseus nerve is the deep terminal branch of radial nerve. It is the chief nerve of the back of forearm.
It begins at the cubital fossa and passes through supinator muscle to reach the back of forearm.
It ends in a pseudoganglion in the 4th compartment of extensor retinaculum.
Branches
Muscular branches – to the extensor group of muscles
To extensor carpi radialis brevis , supinator , extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, abductor pollicis longus, extensor policis brevis, extensor pollicis longus, extensor indicis.
Articular branches to wrist joint, distal radioulnar joint.
Sensory branches to radius and ulna.
RETINACULA AND SPACES OF HAND
Name the spaces in the palm. Describe the boundaries of midpalmar space. Add a note on its applied anatomy (LE)
Boundaries and contents of midpalmar space (SA) Spaces in the palm-
Midpalmar space
Thenar space
Web space
Pulp space
Midpalmar space
Boundaries-
Anterior
skin, superficial fascia, medial part of palmar aponeurosis, superficial palmar arch, ulnar bursa
Posterior
3rd and 4th doral and palmar interossei with the anterior interosseous fascia covering them
Medial
hypothenar septum (medial palmar septum)
Lateral
midpalmar septum separating it from the thenar space
Distal
space is continuous with medial 3 web spaces through lumbrical canals
Proximal
space is continuous with space of parona in the forearm between flexor tendons and pronator quadratus
Contents - 2nd, 3rd, 4th lumbrical muscles
Applied anatomy - Infections may spread into the midpalmar space through ulnar bursa and can spread to lumbrical canals and web space.The pus in the space is drained by putting vertical incision in the medial 2 web spaces
FLEXOR RETINACULUM OF HAND (SE)
FLEXOR RETINACULUM ATTACHMENTS (SA)
STRUCTURES SUPERFICIAL TO FLEXOR RETINACULUM (SA) It is thickened part of deep fascia over the carpus Attachments
Medial
pisiform, hook of hamate Lateral
tubercle of scaphoid, crest of trapezium. Near the trapezium it splits into two slips, superficial attaches to crest and deep to medial margin of groove on trapezium.
Upper margin-
continues with deep fascia of forearm and Palmaris longus
Lower margin-
gives attachment to the apex of palmar aponeurosis
It gives origin to thenar and hypothenar muscles of hand
Relations
Superficial to flexor retinaculum
ulnar nerve, ulnar vessels, palmar cutaneous branch of ulnar nerve, tendon of Palmaris longus, palmar cutaneous branch of median nerve, superficial palmar branch of radial artery
Deep to flexor retinaculum
long flexor tendons of digits, median nerve Applied anatomy-
carpal tunnel syndrome-
median nerve is compressed leading to burning pain along three and half fingers and wastage of thenar muscles
CARPAL TUNNEL SYNDROME (SE)
Carpal tunnel syndrome (CTS) is a medical condition due to compression of the median nerve as it travels through the wrist at the carpal tunnel
Causes- Exact cause is not known
Risk factors include obesity, repetitive wrist work eg computer work vibrating tools, pregnancy hypothyroidism and rheumatoid arthritis.
Symptoms
The main symptoms are pain, numbness and tingling, in the thumb, index finger, middle finger, and the thumb side of the ring fingers.
Symptoms typically start gradually and during the night. Pain may extend up the arm. Weak grip strength may occur and after a long period of time the thenar muscles may waste away. In more than half of cases both sides are affected.
Treatment
Symptoms can be improved by wearing a wrist splint or with corticosteroid injections. Surgery to cut the transverse carpal ligament is effective with better results
PALMAR APONEUROSIS (SE)
It is triangular deep fascia which occupies central area of palm and has following features
Apex
It is directed proximally and attached to flexor retinaculum. Base
Is directed distally and divides into 4 slips. Each slip divides into two bands one passing to skin, and the other passing deep to the root of finger and attached to fibrous flexor sheath and deep transverse ligaments.
Medial and lateral borders
Are continuous with thinner deep fascia covering hypothenar and thenar muscles and sends septa posteriorly.
Functions
The palmar aponeurosis give firm attachment to the overlying skin, improves the grip and protect the underlying tendons
Clinical anatomy - Dupuytren’s contracture- localized thickening and contracture of palmar aponeurosis which limits the hand functioning and eventually disable the hand.
EXTENSOR RETINACULUM OF WRIST (SE)
Attachments- Medial-
triquetral, pisiform bones Lateral-
lower part of anterior border of radius
The retinaculum sends five septa and divides the space beneath it into 6 compartments. The structures passing through the compartments are as follows
1st compartment- abductor pollicis longus, extensor pollicis brevis
2nd compartment- extensor carpi radialis longus, extensor carpi radialis brevis
3rd compartment- extensor pollicis longus
4th compartment- extensor digitorum, extensor indicis, anterior interosseous artery, posterior interosseous nerve
5th compartment- extensor digiti minimi
6th compartment- extensor carpi ulnaris
STRUCTURES PASSING THROUGH CARPAL TUNNEL (SA) Tendons of Flexor digitorum superficialis
flexor digitorum profundus median nerve
STRUCTURES AFFECTED IN CARPAL TUNNEL SYNDROME (SA) Tendons of Flexor digitorum superficialis
flexor digitorum profundus median nerve
PALMAR APONEUROSIS (SA)
The palmar aponeurosis give firm attachment to the overlying skin, improves the grip and protect the underlying tendons
Apex is directed proximally and attached to flexor retinaculum
Base is directed distally and divides into 4 slips. Each slip is attached to skin, fibrous flexor sheath and deep transverse ligaments.
Medial and lateral borders are continuous with thinner deep fascia covering hypothenar and thenar muscles and sends septa posteriorly.
FASCIAL SPACES OF HAND (SA)
They are certain potential spaces which become obvious when infected Dorsal spaces of hand-Dorsal subcutaneous space
Dorsal subaponeurotic space posterior interosseous space Palmar spaces-
Midpalmar space Thenar space Web space Pulp space
CONTENTS OF 4TH COMPARTMENT UNDER EXTENSOR RETINACULUM OF HAND (SA)
extensor digitorum extensor indicis
anterior interosseous artery posterior interosseous nerve
CARPAL TUNNEL SYNDROME (SA)
median nerve is compressed due to thickening of synovial sheaths of fingers or fracture dislocation of carpal bones leading to burning pain along three and half fingers and wastage of thenar muscles
DUPUYTREN’S CONTRACTURE (SA)
It is a localized thickening and contracture of palmar aponeurosis which limits the hand functioning and eventually disable the hand
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