Areas in the Upper Limb Flashcards
What is the cubital fossa?
Cubital fossa is a triangular hollow situated on the front of the elbow.
Boundaries of cubital fossa.
Laterally – Medial border of the brachioradialis.
Medially – Lateral border of the pronator teres.
Base/ Superior – Imaginary line joining the front of
two epicondyles of the humerus.
Apex – Formed by area where brachioradialis crosses
the pronator teres muscle.
Roof – bicipital aponeurosis, superficial fascia, subcutaneous fat and skin.
Floor – brachialis (proximally) and supinator (distally).
Contents of cubital fossa.
From medial to lateral, they include:
Median nerve.
Termination of brachial artery.
Tendon of Biceps brachii.
Radial nerve.
Where is the median cubital vein located
Roof of cubital fossa.
Clinical relevance of CF
The median cubital vein is the vein of
choice for intravenous injections.
It is used for introducing cardiac catheters.
The blood pressure is universally recorded by
auscultating the brachial artery in front of the
elbow
Describe the axilla.
The axilla is a pyramidal space situated
between the upper part of the arm and the chest wall.
The axilla has what shape
Pyramidal shape with an apex and a base.
Apex of A is formed by
Apex – formed by lateral border of the first rib, superior border of scapula, and the posterior border of the clavicle.
List what passes through the cervicoaxillary canal to the axilla.
The axillary artery, axillary vein
and the brachial plexus .
Base of A is formed by
Skin, superficial and axillary fasciae.
Anterior wall of A is formed by
The pectoralis major.
The clavipectoral fascia.
Pectoralis minor.
Posterior wall of A is formed by
Subscapularis.
Teres major.
Latissimus dorsi.
Medial wall of A is formed by
Upper four ribs with their intercostal muscles.
Upper part of the serratus anterior muscle.
Lateral wall of A is formed by
Bicipital groove.
Coracobrachialis and short head of the biceps
brachii.
Contents of axilla
Axillary artery and its branches.
Axillary vein and its tributaries.
Brachial plexus.
Axillary lymph nodes.
Axillary fat.
Routes by which structures leave the axilla
Quadrangular space.
Clavipectoral triangle.
Clinical correlates of axilla
Thoracic outlet syndrome.
What is TOS
It is a condition where the contents found in the apex, the vessels and nerves become compressed between the bones.
Common causes of TOS
Trauma – e.g. fractured clavicle.
Repetitive movements – seen commonly in occupations that require lifting of the arms.
Cervical rib – an extra rib which arises from the seventh cervical vertebra.
TOS Presents with what
Pain in the affected limb.
Tingling.
Muscle weakness.
Discoloration.
Describe the anatomical snuffbox.
The anatomical snuffbox is triangular
depression on the posterolateral side of the wrist.
ASB is best seen
when the thumb is extended
Another name for ASB
Radial fossa.
Borders or boundaries. of ASB
Ulnar (medial) border: Tendon of the extensor pollicis longus.
Radial (lateral) border: Tendons of the extensor pollicis brevis and abductor pollicis longus.
Proximal border: Styloid process of the radius.
Floor: Carpal bones; scaphoid and trapezium.
Roof: Skin.
Contents of ASB
Radial artery (deep).
Superficial branch of radial nerve.
Cephalic vein.
Clinical correlates of anatomical snuffbox
Scaphoid fracture- Fracture of the scaphoid bone. Presents with pain and tenderness in the anatomical snuffbox.
Describe the extensor retinaculum.
The deep fascia on the back of the wrist is thickened to
form the extensor retinaculum which holds the extensor
tendons in place. It is an oblique band, directed
downwards and medially.
Attachments of the extensor retinaculum.
Laterally: Lower part of the sharp anterior border of
the radius.
Medially:
I. Styloid process of the ulna
ii. Triquetral
iii. Pisiform
Extensor retinaculum has how many compartments
6
List the compartments.
I * Abductor pollicis longus
* Extensor pollicis brevis
II * Extensor carpi radialis longus
* Extensor carpi radialis brevis
III * Extensor pollicis longus
IV * Extensor digitorum
* Extensor indicis
* Posterior interosseous nerve
* Anterior interosseous artery
V * Extensor digiti minimi
VI * Extensor carpi ulnaris
Describe the carpal tunnel
The carpal tunnel is a narrow passageway found on the anterior portion of the wrist.
It serves as the entrance to the palm for several tendons and the median nerve.
Borders of carpal tunnel
Carpal arch.
Flexor retinaculum.
Describe the carpal arch.
It is concave on the palmar side, forming the base and sides of the carpal tunnel.
Carpal arch is formed laterally by
The scaphoid and trapezium tubercles.
Carpal arch is formed medially by
The hook of the hamate and the pisiform
Describe the flexor retinaculum
It is a thick connective tissue which forms the roof of the carpal tunnel.
It turns the carpal arch into the carpal tunnel by bridging the space between the medial and lateral parts of the arch.
It spans between the hook of hamate and pisiform (medially) to the scaphoid and trapezium (laterally).
Contents of carpal tunnel
9 tendons- 4 from FDS.
4 from FDP.
1 from FPL.
1 nerve- Median nerve.
FDS and FDP are surrounded by a single synovial sheath.
FPL is surrounded by its own synovial sheath.
Once it passes through the carpal tunnel, the median nerve divides into 2 branches, what are they?
The recurrent branch and palmar digital nerves.
Palmar digital branch supplies
The palmar digital nerves give sensory innervation to the palmar skin and dorsal nail beds of the lateral three and a half digits.
They also provide motor innervation to the lateral two lumbricals.
Recurrent branch supplies
Thenar group of muscles
Clinical correlates of carpal tunnel
Carpal tunnel syndrome.
Describe the CTS
Compression of the median nerve within the carpal tunnel.
Most common mononeuropathy.
Clinical Features of CTS
They include numbness, tingling and pain in the distribution of the median nerve.
If CTS left untreated,what can happen
CTS can cause weakness and atrophy of the thenar muscles.
Describe the Guyons canal
The ulnar (Guyon’s) canal is a fibro-osseous tunnel located at the level of the palm.
It transmits the ulnar neurovascular bundle from the forearm into the hand.
Borders of the guyon canal
Medial (ulnar) – pisiform, flexor carpi ulnaris tendon, abductor digiti minimi muscle.
Lateral (radial) – hook of hamate.
Roof – palmar carpal ligament.
Floor – flexor retinaculum, pisohamate ligament, and hypothenar muscles.
Length of guyons canal
4cm in length.
Guyons canal extends from where to where
It extends from the proximal aspect of the pisiform bone to the origin of the hypothenar muscles at the hook of hamate.
Contents of guyons canal
Ulnar nerve
Ulnar artery
Venae comittantes of ulnar artery.
Lymphatic vessels.
Clinical correlates of guyons canal
Ulnar canal syndrome refers to compression of the ulnar nerve within the ulnar canal. The most common causes are ganglion cyst, lipoma and trauma.
Clinical features of UCS
Sensory – pain and paraesthesia ulnar 1 1/2 digits
Motor- Weakness of thumb adduction (adductor pollicis)
Weakness of finger abduction and adduction (interossei)
Weakness of little finger flexion, abduction and opposition (hypothenar muscles)
Describe the quadrangular space
The quadrangular space is an anatomical space is the posterior axilla region.
It provides a conduit for structures to pass between the axilla and the posterior compartment of the arm.
Shape of QS
Rectangular
Borders of QS
Superior – inferior margin of teres minor.
Lateral – surgical neck of the humerus.
Medial – long head of triceps brachii.
Inferior – superior aspect of teres major.
Contents of QS
It contains the axillary nerve and posterior circumflex humeral artery and vein.
Clinical correlate of QS
Quadrangular space syndrome refers to compression of the axillary nerve and posterior circumflex humeral artery as they pass through the quadrangular space.
Compression is thought to occur secondary to hypertrophy of the muscular borders of the space.
