Lecture 4.1: Overview of the Upper Limb and Pectoral Region Flashcards
Regions of the Upper Limb (8)
- Pectoral
- Shoulder
- Axillary
- Brachial
- Cubital
- Antebrachial
- Carpal
- Hand
What encloses the muscles of the upper limb?
Deep Fascia
Intermuscular Septa: Function? Origin?
- Intermuscular septa arise from the deep fascia
* Separates limb into discrete compartments
Compartments of the Upper Limb: Anterior
Mostly Flexor
Compartments of the Upper Limb: Posterior
Mostly Extensor
What is an Escharotomy?
The surgical division of the nonviable eschar, the tough, inelastic mass of burnt tissue that results from full-thickness circumferential and near-circumferential skin burns
The eschar, by virtue of its inelasticity, results in the burn-induced compartment syndrome
What is Compartment Syndrome?
- Increased pressure within a closed anatomical space
- Compromises blood supply → ischaemia
- Temporary/permanent damage to muscles and nerves
- Acute (usually fracture) or chronic (e.g. exercise)
Symptoms of Compartment Syndrome
• Pain+++,
• Parasthesia
• Peripheral pulses usually present until late
[• Care not to confuse with acute arterial injury (5 Ps)]
Treatment for Compartment Syndrome
Fasciotomy: tissue that surrounds the area is cut open to relieve pressure
What is Parasthesia?
A burning or prickling sensation that is usually felt in the hands, arms, legs, or feet, but can also occur in other parts of the body
Upper Limb Bony Structures: Shoulder Girdle
- Clavicle
* Scapula
Upper Limb Bony Structures: Arm
- Humerus
* [Elbow Joint]
Upper Limb Bony Structures: Forearm
- Radius is Lateral
* Ulna is Medial
Upper Limb Bony Structures: Hand
- Carpals
- Metacarpals
- Phalanges
What is the Brachial Plexus?
A network of nerves in the shoulder that carries movement and sensory signals from the spinal cord to the arms and hand
Where does the Brachial Plexus originate from?
- Originates from cervical and thoracic spinal cord levels
* C5, C6, C7, C8, T1
How is the Brachial Plexus formed?
Begins in neck –> axilla –> arm –> forearm –> hand
What does the Brachial Plexus consist of?
What are the Main Nerves of the Upper Limb? (5)
- Axillary Nerve
- Musculocutaneous Nerve
- Median Nerve
- Radial Nerve
- Ulnar Nerve
Main Nerves of the Upper Limb: Axillary Nerve
- Deltoid minor
* Teres minor
Main Nerves of the Upper Limb: Musculocutaneous Nerve
• Anterior compartment of arm
Main Nerves of the Upper Limb: Median Nerve
- Most anterior compartment forearm
- Thenar muscles
- Lumbricals 1 and 2
Main Nerves of the Upper Limb: Radial Nerve
- Posterior compartment arm
* Forearm
Main Nerves of the Upper Limb: Ulnar Nerve
- Small muscles of hand
* 1½ anterior forearm muscles
What are the Arteries of the Upper Limb? (5)
- Subclavian Artery
- Axillary Artery
- Brachial Artery
- Radial Artery
- Ulnar Artery
Arteries of the Upper Limb: Subclavian Artery
- Structures in the neck
* Part of the thoracic wall and entire upper limb
Arteries of the Upper Limb: Axillary Artery
- Continuation of the subclavian
* Beginning at the lateral border of the first rib
Arteries of the Upper Limb: Brachial Artery
- Continuation of the axillary
- Beginning at the lateral
- Lower border of the teres major (muscle)
Arteries of the Upper Limb in the Cubital Fossa
- Cubital Fossa is the area of transition between the arm and the forearm
- It is located in a depression on the anterior surface of the elbow joint
- The brachial artery bifurcates into the Radial and Ulnar arteries of the forearm
Arteries of the Upper Limb in Hand
- Ulnar and Radial Arteries give rise to palmar arches
* Superficial and Deep → Supply Digits
What is another name for Deep Veins?
Vena Commitantes accompany major arteries and carry the same name as the artery
What are the Deep Veins of the Upper Limb? (5)
- Subclavian Vein
- Axillary Vein
- Brachial Vein
- Radial Vein
- Ulnar Vein
Where are the Superficial Veins of Upper Limb
Superficial veins do NOT run with arteries and are subcutaneous
What are the Superficial Veins of Upper Limb? (3)
- Cephalic Vein
- Median Cubital Vein
- Basilic Vein
Lymphatic System: Lymph
- Tissue Fluid
- Plasma Proteins
- WBCs, especially lymphocytes, the cells that attack bacteria in the blood
Lymphatic System: Lymph Nodes
- A small bean-shaped structure that is part of the body’s immune system
- Filters with immune function
Lymphatic System: Vessels
- Drains lymph via network of vessels (valves) throughout the body
- Return the fluid to the venous system through two collecting ducts
- Run in one direction, towards heart
What is Lymphoedema?
Tissue swelling caused by an accumulation of protein-rich fluid (interstitial fluid) that’s usually drained through the body’s lymphatic system
Lymphatic System: Lymphoid Tissue
- Lymphoid tissues are organised structures that support immune responses
- Lymphoid tissue forms aggregations at body entrances (e.g. tonsils)
5 Types of Lymphoid Tissues
- Lymph Nodes
- Tonsils
- Spleen
- Peyer’s Patches
- Mucosa Associated Lymphoid Tissue (MALT)
What does the Pectoral Region consist of?
- Superficial compartment containing skin
- Superficial fascia
- Breast tissue
- Deep compartment containing muscles and associated structures
What in the Pectoral Region anchors the upper limb to the trunk?
What in the Pectoral Region anchors the upper limb to the trunk?
- Sternoclavicular joint
- Muscles
- Ligaments
Scapula: Acromion
Palpable bony shelf above shoulder
Scapula: Coracoid Process
Palpable below the lateral clavicle
Humerus: Greater Tubercle
More lateral on the humerus
Humerus: Lesser Tubercle
On medial side of humerus
Clavicle
- S-shaped bone
- Connects scapula to sternum
- Acts as a strut supporting the upper limb
- Transmits forces to axial skeleton
- Most commonly broken bone
Sternoclavicular Joint
- Only joint between the upper limb and axial skeleton
- Supported by the Costoclavicular Ligament
- Functions as a synovial ball & socket joint
- Dislocation is rare
Acromioclavicular Joint
- Clavicle and Scapula’s Acromion meet
- Joint line passes from anterior to posterior
- Supported by the Coracoacromial Ligament
- Dislocation (shoulder separation) → visible deformity
- Synovial plane joint Dislocation possible
Coracoacromial Ligament
- Supports the shoulder joint superiorly
- Can be ruptured by superiorly directed forces
- Can impinge on supraspinatus/subacromial bursa
Clavicle Fracture
- 3 Area: Lateral, Middle, Medial
- Weakest point is junction between the middle & lateral thirds
- Risk of fracture from a fall onto outstretched limb/ onto the lateral shoulder
Pectoral Girdle Muscles: Pectoralis Major
What does it attach to? What nerve supplies it? Function?
• Adducts & medially rotates the shoulder
• Accessory breathing muscle
• Medial & Lateral Pectoral Nerve
• Attaches to the clavicle, sternum & adjacent costal cartilages and the lateral
lip of the intertubercular groove (humerus)
Pectoral Girdle Muscles: Pectoralis Minor
What does it attach to? What nerve supplies it? Function? Shape?
- Depresses & protracts the scapula
- ‘Divides’ axillary artery into 3 parts
- Medial Pectoral Nerve
- Attaches to ribs 3-5 and the coracoid process
Pectoral Girdle Muscles: Serratus Anterior
What does it attach to? What nerve supplies it? Function?
- Protracts scapula (reaching out) & holds it close to the thoracic wall
- Attaches to ribs 1-8 anteriorly and medial scapula border
- Supplied by Long Thoracic Nerve
- Allow you to do press ups without scapula winging
Pectoral Girdle Muscles: Deltoid
What does it attach to? What nerve supplies it?
- Attaches to lateral clavicle, acromion, scapula spine and humerus
- Axillary nerve
Pectoral Girdle Muscles: Trapezius
What does it attach to? Origins? Insertions? What nerve supplies it?
It originates on the occipital bone, the ligamentum nuchae, and the spinous processes of T01–T12
The trapezius inserts on the lateral third of the clavicle, as well as the acromion and scapular spine of the scapula
Accessory n. (CN XI)
Pectoral Girdle Muscles: Trapezius Movement
Elevates, retracts and depresses the scapula
Pectoral Girdle Muscles: Latissimus Dorsi
What does it attach to? Origins? Insertions? What nerve supplies it?
Origin is from spinous processes of thoracic T7–T12, thoracolumbar fascia, iliac crest and inferior 3 or 4 ribs, inferior angle of scapula
There is insertion on floor of intertubercular groove of the humerus
Thoracodorsal n.
Pectoral Girdle Muscles: Latissimus Dorsi Movement
- Extends, adducts and medially rotates humerus
* Can raise the trunk to the arm e.g.dips/climbing
Pectoral Girdle Muscles: Rhomboid Major
What does it attach to? Origins? Insertions? What nerve supplies it?
- Origin is T2-T5 Spinous Processes
- Insertion on the medial border of the scapula
- Dorsal scapula n.
Pectoral Girdle Muscles: Rhomboid Minor
What does it attach to? Origins? Insertions? What nerve supplies it?
- Nuchal ligaments and spinous processes of C7-T1
- Medial border of scapula, superior to insertion of rhomboid major muscle
- Dorsal scapula n.
Pectoral Girdle Muscles: Rhomboid Major and Rhomboid Minor Movement
Retract & fix position of scapula
Pectoral Girdle Muscles: Levator Scapulae
What does it attach to? Origins? Insertions? What nerve supplies it?
- Origin from posterior tubercles of transverse spinal processes C1-C4
- Insertion into superior part of medial border of the scapula
- Dorsal scapula n. & C3-4
Pectoral Girdle Muscles: Levator Scapulae Movement
Elevates & rotates scapula
Pectoral Girdle Muscles: Teres Major
What does it attach to? Origins? Insertions? What nerve supplies it?
- Origin is Lateral Border of Scapula
- Insertion is Greater Tubercle of Humerus
- Lower Subscapular n.
Pectoral Girdle Muscles: Teres Major Movement
Adduction & medial rotation of humerus
Pectoral Girdle Muscles: Serratus Anterior
What does it attach to? Origins? Insertions? What nerve supplies it?
- Originates at the 1st to 8/9th Rib (mid anterior of ribs)
- Insertion at the anterior surface of the medial border of the scapula
- Long thoracic n.
Pectoral Girdle Muscles: Serratus Anterior Movement
- Protracts scapula (reaching out)
* Holds it close to the thoracic wall
