Brachial Plexus Quiz: Pectoral Girdle Function and More

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Questions and Answers

What is the significance of the clavicle in the human body?

It is the only bony attachment of the upper limb to the axial skeleton. (correct)

It is the last long bone to start ossification.

It is the first bone to fuse during skeletal development.

It is the only bone that articulates with the scapula.

At what age does the scale-like ossification center at the sternal end of the clavicle begin to fuse with the diaphysis?

5-6 years

30-35 years

18-25 years (correct)

12-15 years

Which bone in the human body is the first long bone to begin ossification?

Radius

Femur

Clavicle (correct)

Humerus

During skeletal development, what can the fusion of the clavicle be mistaken for?

Fracture Signup and view all the answers

Which bone does the clavicle articulate with proximally and distally?

Sternum and scapula Signup and view all the answers

Which part of the scapula acts as an attachment site for the trapezius muscle?

Acromion Signup and view all the answers

What is the primary function of the coracoid process on the scapula?

Serves as an attachment site for muscles like pectoralis major Signup and view all the answers

Where is the glenoid cavity located on the scapula?

Found on the ventral side of the scapula's spine Signup and view all the answers

How many main bones make up the shoulder girdle?

Two Signup and view all the answers

Which part of the skeletal structure connects the axial skeleton to the appendicular skeleton?

Shoulder girdle Signup and view all the answers

Which part of the humerus is more commonly associated with fractures?

Surgical neck Signup and view all the answers

Where is the deltoid tuberosity located in relation to the humerus head?

Distal Signup and view all the answers

Which part of the humerus is commonly referred to as a 'bump'?

Greater tubercle Signup and view all the answers

In the anatomy of the humerus, which part separates the greater and lesser tubercles?

Intertubercular groove Signup and view all the answers

Which part of the humerus is most proximal?

Anatomical neck Signup and view all the answers

What type of joint is the sternoclavicular joint?

Saddle joint Signup and view all the answers

Which structure divides the sternoclavicular joint into two compartments?

Fibrocartilaginous disc Signup and view all the answers

Where does the clavicle articulate with the scapula?

Acromioclavicular joint Signup and view all the answers

Which joint allows movements of the shoulder girdle?

Acromioclavicular joint Signup and view all the answers

Why is the glenoid cavity considered shallow in the shoulder joint?

To ensure stability of the shoulder joint Signup and view all the answers

Which ligament is responsible for shoulder stability by connecting the acromion and the clavicle?

Coracoclavicular ligament Signup and view all the answers

Which joint in the shoulder region is susceptible to dislocation when falling on an outstretched arm?

Acromioclavicular joint Signup and view all the answers

What type of joint is the acromioclavicular joint?

Plane joint Signup and view all the answers

In a complete shoulder separation injury, which ligaments are ruptured?

Acromioclavicular, trapezoid, conoid Signup and view all the answers

What is the common outcome of a fall capable of separating the AC joint?

Fracture of the clavicle Signup and view all the answers

What structure deepens the glenoid cavity in the shoulder joint?

Glenoid labrum Signup and view all the answers

Which ligament plays a role in stabilizing the shoulder joint by connecting the acromion and the coracoid process?

Coracoacromial ligament Signup and view all the answers

Which structure separates the supra and infraspinatus muscles from the acromion and coracoacromial ligament?

Subdeltoid bursa Signup and view all the answers

Which type of joint is the glenohumeral joint in the shoulder region?

Ball-and-socket joint Signup and view all the answers

Which anatomical feature in the shoulder provides attachment for the trapezius muscle?

Acromion Signup and view all the answers

What is the primary function of the acromion in the shoulder joint?

Stabilizing the glenohumeral joint Signup and view all the answers

In which type of shoulder dislocation does the humeral head often end up in a subcoracoid location?

Subglenoid dislocation Signup and view all the answers

What is the structure on the scapula that serves as an attachment site for the trapezius muscle?

Coracoid process Signup and view all the answers

Which part of the shoulder girdle is responsible for connecting the axial skeleton to the appendicular skeleton?

Clavicle Signup and view all the answers

Why are shoulder dislocations, particularly anterior dislocations, more common in patients younger than 30 years?

Because of weaker ligaments and developing bone structure Signup and view all the answers

Which muscle originates from the spine of the scapula, acromion, and lateral 1/3 of the clavicle to insert on the deltoid tuberosity of the humerus?

Deltoid Signup and view all the answers

Which nerve innervates the deltoid muscle responsible for abducting the arm?

Axillary nerve Signup and view all the answers

Which structure on the scapula serves as an attachment point for the trapezius muscle?

Acromion Signup and view all the answers

What function does the acromion serve in the shoulder joint?

Stabilization of the shoulder joint Signup and view all the answers

Where does the deltoid tuberosity attach on the humerus in relation to the humeral head?

Lateral aspect Signup and view all the answers

Which structure originates from the anterior surface of the scapula and inserts on the lesser tubercle of the humerus?

Subscapularis Signup and view all the answers

What nerve innervates the teres minor muscle, which is a lateral rotator located deep to the deltoid muscle?

Axillary nerve Signup and view all the answers

In the shoulder girdle, which muscle is primarily responsible for initiating the first 15 degrees of abduction?

Supraspinatus Signup and view all the answers

Which muscle, innervated by the suprascapular nerve, is a lateral (external) rotator of the humerus?

Infraspinatus Signup and view all the answers

Which muscle, originating from the posterior surface of the scapula, provides stability to the glenohumeral joint?

Teres minor Signup and view all the answers

Which muscle is most vulnerable to injury due to repeated abduction and flexion?

Supraspinatus Signup and view all the answers

What is the primary function of the acromion in relation to the shoulder joint?

To prevent impingement of the supraspinatus tendon Signup and view all the answers

Where does the teres major muscle originate from?

Inferior angle of the scapula Signup and view all the answers

Which structure forms a musculotendinous cuff around the shoulder joint?

Tendons of insertion of rotator cuff muscles Signup and view all the answers

What causes pain in the supraspinatus (impingement) syndrome between 60 and 120° of abduction?

Thickening of the supraspinatus tendon Signup and view all the answers

Which muscle originates from the infraglenoid tubercle and passes anterior to the teres minor but posterior to the teres major?

Triceps brachii Signup and view all the answers

Which muscle provides stability to the glenohumeral joint by connecting the acromion to the humerus?

Deltoid muscle Signup and view all the answers

Which structure creates borders for the triangular space in the shoulder, allowing structures to pass through?

Teres minor and teres major Signup and view all the answers

What is the primary function of the acromion within the shoulder joint anatomy?

Protect underlying structures Signup and view all the answers

Which part of the humerus separates the greater tubercle from the lesser tubercle?

Intertubercular groove Signup and view all the answers

Through which space do the radial nerve and deep artery of the arm pass?

Triangular space Signup and view all the answers

What mnemonic is used to remember that the artery is superficial and the nerve is deep to the transverse scapular ligament?

Army goes over the bridge; Navy goes under the bridge Signup and view all the answers

Which vessels provide collateral circulation to the upper limb if the proximal part of the axillary artery becomes occluded?

Circumflex scapula and dorsalscapular arteries Signup and view all the answers

Which structures supply both the supra- and infraspinatus muscles?

Suprascapular vessels and nerve Signup and view all the answers

What do the axial rich vascular anastomoses around the shoulder joint primarily supply?

16 muscles attaching to the scapula Signup and view all the answers

Which muscle retracts and medially rotates the scapula?

Trapezius muscle Signup and view all the answers

Where does the trapezius muscle insert?

Medial border of the scapula Signup and view all the answers

Which nerve innervates the latissimus dorsi muscle?

Thoracodorsal nerve Signup and view all the answers

What is the primary function of the coracoid process on the scapula?

Flexor of the arm Signup and view all the answers

Which structure deepens the glenoid cavity?

Coracoid process Signup and view all the answers

Which muscle is primarily responsible for protracting and laterally rotating the scapula?

Pectoralis major Signup and view all the answers

Injury to which nerve can lead to the clinical presentation of 'winged scapula'?

Long thoracic nerve Signup and view all the answers

What is the primary function of the acromion in relation to the shoulder joint?

Forms the bony prominence at the back of the shoulder Signup and view all the answers

Which structure on the scapula serves as an attachment point for the deltoid muscle?

Acromion Signup and view all the answers

What can cause injury to the long thoracic nerve leading to 'winged scapula'?

Overuse Signup and view all the answers

What nerve innervates the levator scapulae muscle, which attaches to the transverse processes of the upper cervical vertebrae and elevates the scapula?

Dorsal scapular nerve Signup and view all the answers

Which artery changes its name to the axillary artery at the lateral border of the first rib and continues through the axilla to the inferior border of the teres major muscle?

Subclavian artery Signup and view all the answers

In the shoulder region, where does the subclavian artery change its name to the axillary artery?

At the lateral border of the first rib Signup and view all the answers

Which muscle primarily elevates the scapula by attaching to the superior angle of the scapula and providing attachment to the posterior rib cage?

Rhomboid major Signup and view all the answers

What structure separates the greater tubercle from the lesser tubercle on the humerus?

Intertubercular groove Signup and view all the answers

What is the primary function of the acromion in the shoulder joint?

Stabilizing the glenohumeral joint by connecting the acromion to the humerus Signup and view all the answers

Which structure attaches to the coracoid process on the scapula?

Pectoralis minor muscle Signup and view all the answers

Where is the glenoid cavity located in relation to the scapula?

On the anterior surface of the scapula Signup and view all the answers

What is the function of the coracoid process in relation to the shoulder joint?

Attachment site for the biceps brachii muscle Signup and view all the answers

Which part of the skeletal structure attaches to the posterior rib cage?

Coracoid process Signup and view all the answers

What structure serves as an attachment site for the deltoid muscle and is located at the lateral end of the scapular spine?

Acromion Signup and view all the answers

Which anatomical feature in the shoulder provides attachment for multiple muscles, including the pectoralis minor, coracobrachialis, and biceps brachii?

Coracoid process Signup and view all the answers

In the shoulder region, what structure acts as the socket for the head of the humerus and contributes to shoulder joint stability?

Glenoid cavity Signup and view all the answers

Which part of the skeletal structure provides attachment sites for muscles that stabilize and move the scapula, such as serratus anterior and rhomboids?

Posterior rib cage Signup and view all the answers

What structure, when deepened by the glenoid labrum, enhances the stability of the shoulder joint by increasing the contact area with the humeral head?

Glenoid cavity Signup and view all the answers

Where does the axillary vein change its name to the subclavian vein?

Lateral border of the 1st rib Signup and view all the answers

Where does the cephalic vein empty into the axillary vein?

Lateral border of the 1st rib Signup and view all the answers

Which structure is created by spinal nerves from spinal cord levels C5 through T1?

Brachial plexus Signup and view all the answers

Where is the coracoid process located in relation to the shoulder girdle?

Anteromedial aspect Signup and view all the answers

What provides stability to the glenohumeral joint by connecting the acromion to the humerus?

Deltoid muscle Signup and view all the answers

Match the following dermatomes with their sensory innervation:

C5 = Lateral side of the forearm and thumb C6 = Skin of the neck, shoulder, inner aspect of the biceps, and ulnar half of the forearm C7 = Lateral side of the back of the hand and the ulnar half of the first web space T1 = Medial side of the forearm and hand Signup and view all the answers

Match the following dermatomes with their motor functions:

C5 = N/A C6 = Flexion of the elbow joint and wrist extension C7 = Controlling finger extension and abduction C8 = Grip strength and hand intrinsics Signup and view all the answers

Match the following dermatomes with their characteristic sensory innervation:

C5 = Axillary region C6 = Inner aspect of the biceps C7 = Deltoid region T1 = Medial side of the arm Signup and view all the answers

Match the following dermatomes with their potential clinical implications:

C5 = Thoracic outlet syndrome C6 = Elbow flexion limitations C7 = Finger extension weakness T1 = 'Claw hand' deformity Signup and view all the answers

Match the following dermatomes with their potential injury associations:

C5 = Cervical rib injury C6 = 'Popeye' deformity C7 = 'Drop wrist' presentation T1 = 'Klumpke's Palsy' Signup and view all the answers

Match the following anatomical features of the humerus with their descriptions:

Intertubercular groove = Located on the anterior side between the greater and lesser tubercles Capitulum = Located at the distal end for articulation with the radius of the forearm Radial groove = Groove in the medial aspect of the humerus for the radial nerve Trochlea = Located at the distal end for articulation with the ulna Signup and view all the answers

Match the following fossa in the humerus with their functions:

Coronoid fossa = Allows full flexion of the forearm at the elbow Olecranon fossa = Allows full extension of the forearm at the elbow Radial fossa = Located anteriorly and allows flexion of the forearm at the elbow Supracondylar ridges = Attachments for muscles of the forearm Signup and view all the answers

Match the following prominences in the distal humerus with their descriptions:

Medial epicondyle = Prominence on the medial side of the elbow Lateral epicondyle = Prominence on the lateral side of the elbow Supracondylar ridges = Extend superiorward from the epicondyles Radial groove = Located in the medial aspect of the humerus for radial nerve Signup and view all the answers

Match the following structures in relation to shoulder joints with their functions:

Acromion = Provides attachment for multiple muscles, including pectoralis minor and coracobrachialis Coracoid process = Acts as an attachment site for trapezius muscle Clavicle = Articulates with scapula proximally and distally Skeletal structure = Provides attachment sites for muscles that stabilize and move scapula Signup and view all the answers

Match the following joints in relation to shoulder stability with their descriptions:

Sternoclavicular joint = Type of joint susceptible to dislocation when falling on an outstretched arm Acromioclavicular joint = Type of joint providing shoulder stability by connecting acromion and clavicle Musculotendinous cuff = Forms around shoulder joint providing stability Transverse scapular ligament = Mnemonic used to remember artery is superficial and nerve is deep Signup and view all the answers

Match the following structures with their primary function in relation to compartment syndrome:

Superficial fascia = Layer directly beneath the skin Deep fascia = Surrounds deep structures and muscles Perivascular sheath = Contains major nerves and arteries Intermuscular septum = Divides limbs into compartments Signup and view all the answers

Match the following terms with their associated clinical manifestations in compartment syndrome:

Ischaemia = Restriction in blood supply Tingling and numbness = Compression of intracompartmental nerves Muscle damage = Caused by ischaemia leading to swelling Compartment contents may die = If untreated due to pressure buildup Signup and view all the answers

Match the following actions with their outcomes in compartment syndrome:

Pressure buildup in deep fasciae compartments = Can cause ischaemia and compromise nerves Fasciotomy = Cut in deep fascia to prevent pressure buildup Blood leaking into tissues via traumatic injury = Can also cause compartment syndrome Returning circulation after fasciotomy = Prevents further damage Signup and view all the answers

Match the following terms with their anatomical locations in the arm compartments:

Anterior, flexor compartment = Separated by an intermuscular septum Posterior, extensor compartment = Separated by an intermuscular septum Tibial, fibular and calf regions = Where deep fasciae are not expansible Arm compartments = Can lead to compartment syndrome if pressure builds up Signup and view all the answers

Match the following terms with their descriptions related to compartment syndrome treatment:

Compartment syndrome = Caused by pressure buildup within non-expansible deep fasciae compartments Low pressure blood vessels compression = Results in ischaemia, tingling, numbness, and nerve compromise Fasciotomy procedure = Involves cutting the deep fascia covering the compartment to prevent further damage Preventing pressure buildup after returning circulation = Key step in managing compartment syndrome Signup and view all the answers

Match the following parts of the biceps brachii muscle with their respective attachment points:

Long head = Supraglenoid tubercle Short head = Coracoid process Bicipital aponeurosis = Medial forearm Radial tuberosity = Radius Signup and view all the answers

Match the following joints crossed by the biceps brachii muscle with their primary function:

Glenohumeral joint = Weak flexor of shoulder Elbow joint = Powerful flexor and supinator Signup and view all the answers

Match the following anatomical features related to the biceps brachii muscle with their corresponding functions:

Musculocutaneous nerve = Innervation Supinates and flexes forearm = Function Signup and view all the answers

Match the following shoulder joint structures with their primary functions:

Acromion = Shoulder joint stability Coracoid process = Attachment point for biceps brachii muscle Signup and view all the answers

Match the following muscles with their attachment points in the shoulder region:

Teres major = Originates from inferior angle of scapula Deltoid muscle = Lateral end of scapular spine Signup and view all the answers

Match the muscle with its primary function: The brachialis muscle

Flexes and adducts the arm at the glenohumeral joint = Coracobrachialis muscle Arises from the distal half of the anterior humerus and flexes at the elbow = Brachialis muscle Innervated by the musculocutaneous nerve = Biceps brachii muscle Runs from the coracoid process to the midshaft of the humerus = Coracobrachialis muscle Signup and view all the answers

Match the nerve with its innervation: The musculocutaneous nerve

Pierces and innervates the coracobrachialis muscle = Musculocutaneous nerve Contains mainly C6 and C7 nerve fibers = Musculocutaneous nerve Travels between the biceps and brachialis muscles in the arm = Musculocutaneous nerve Changes names to lateral antebrachial cutaneous nerve at the elbow = Musculocutaneous nerve Signup and view all the answers

Match the anatomical structure with its function: The coracobrachialis muscle

Match the upper extremity nerve branch with its origin: The nerves of the upper extremity arise from which plexus?

Lateral cord of the brachial plexus = Brachial plexus nerves Terminal branches of brachial plexus = Brachial plexus nerves Contains mainly C6 and C7 nerve fibers = Musculocutaneous nerve Changes names to lateral antebrachial cutaneous nerve at the elbow = Musculocutaneous nerve Signup and view all the answers

Match the location with its innervation: Where does the musculocutaneous nerve change names?

Between biceps and brachialis muscles in the arm = At the elbow Innervates biceps and brachialis muscles = During dissection Contains mainly C6 and C7 nerve fibers = At innervation site Pierces coracobrachialis muscle = At innervation site Signup and view all the answers

Match the following nerves with their anatomical course in the arm:

Median nerve = Passes the elbow in the company of the brachial artery Ulnar nerve = Passes posterior to the medial epicondyle Signup and view all the answers

Match the following arteries with their branching patterns in the arm:

Brachial artery = Divides into radial and ulnar arteries at the elbow Axillary artery = Becomes the brachial artery as it passes the teres major muscle Signup and view all the answers

Match the following terms related to shoulder anatomy with their descriptions:

Teres major muscle = Originates from the posterior surface of the scapula Coracoid process = Serves as an attachment site for multiple muscles like pectoralis minor Signup and view all the answers

Match the following anatomical structures with their functions in shoulder stability:

Acromion = Provides stability by connecting to the humerus Axillary artery = Supplies vascular support to the shoulder joint Signup and view all the answers

Match the following joints with their specific locations in shoulder anatomy:

Sternoclavicular joint = Divided into two compartments by a specific structure Glenoid cavity = Deepened by a specific structure Signup and view all the answers

Match the following anatomical structures with their function in shoulder stability:

Coracohumeral ligament = Connects the coracoid process to the humerus for stability Glenoid labrum = Deepens the glenoid cavity for better articulation with the humerus Acromioclavicular ligament = Connects the acromion process to the clavicle for shoulder joint stability Transverse humeral ligament = Holds the long head of the biceps tendon in place in the bicipital groove Signup and view all the answers

Match the following arteries with their branching patterns in the arm:

Brachial artery = Branches into radial and ulnar arteries at the cubital fossa Axillary artery = Continues through the axilla to the inferior border of the teres major muscle Subclavian artery = Branches into vertebral and internal thoracic arteries before becoming axillary artery Radial artery = Travels along the lateral aspect of the forearm after branching from brachial artery Signup and view all the answers

Match the following nerves with their innervation:

Median nerve = Innervates muscles in the anterior compartment of forearm and thenar muscles in hand Ulnar nerve = Innervates muscles in medial part of forearm and intrinsic hand muscles Radial nerve = Innervates muscles in posterior compartment of arm and forearm Musculocutaneous nerve = Innervates muscles in anterior compartment of arm Signup and view all the answers

Match the following anatomical features of the humerus with their descriptions:

Greater tubercle = Lateral prominence where supraspinatus, infraspinatus, and teres minor attach Lesser tubercle = Medial prominence where subscapularis muscle attaches Deltoid tuberosity = Attachment site for deltoid muscle on lateral shaft of humerus Medial epicondyle = Prominence on inner side where common flexor tendons attach Signup and view all the answers

Match the following terms related to shoulder anatomy with their descriptions:

Neurovascular bundle = Located between flexor and extensor muscles on medial side of arm, houses median and ulnar nerves and brachial artery Venae comitantes = Deep veins that accompany major arteries in body, aiding in venous return Superficial veins = Run independently in superficial fascia, important for thermoregulation and blood draw locations Vigorous muscle contraction effect on veins = Compression of deep veins shunts blood into superficial veins making them prominent Signup and view all the answers

Match the upper limb vein with its description:

Cephalic venous system = Lateral superficial vein in the upper limb Basilic system = Medial superficial vein in the upper limb Median cubital vein = Large vein connecting cephalic and basilic systems at the elbow Brachial artery = Artery located directly beneath the bicipital aponeurosis Signup and view all the answers

Match the anatomical regions in the cubital fossa with their contents:

Triangular area marked by imaginary line through epicondyles = Cubital fossa Superficial veins and cutaneous nerves = Contents of cubital fossa Biceps tendon and bicipital aponeurosis = Structures in cubital fossa Brachial artery and larger nerves = Deep structures beneath bicipital aponeurosis Signup and view all the answers

Match the nerve innervation with the muscle responsible for shoulder abduction:

Deltoid muscle = Muscle responsible for abducting the arm Teres minor muscle = Lateral rotator located deep to deltoid muscle Coracobrachialis muscle = Muscle that could elevate scapula by attaching to superior angle Brachialis muscle = Muscle that primarily flexes the elbow joint Signup and view all the answers

Match the anatomical feature with its attachment site for various muscles:

Coracoid process on scapula = Attachment site for multiple muscles including pectoralis minor Spine of scapula, acromion, lateral 1/3 of clavicle = Attachment site for deltoid muscle Greater tubercle of humerus = Attachment site for supraspinatus muscle Acromion of scapula = Attachment site for trapezius muscle Signup and view all the answers

Match the joint stability ligament with its function in the shoulder anatomy:

Coracoclavicular ligament = Connects acromion and clavicle for shoulder stability Glenohumeral ligament = Enhances shoulder joint stability by increasing contact area with humeral head Acromioclavicular ligament = Connects acromion and coracoid process for shoulder stability Transverse humeral ligament = Stabilizes shoulder joint by connecting greater and lesser tubercles Signup and view all the answers

Match the following anatomical structures with their descriptions:

Brachial artery = Part of the brachiocephalic trunk, providing oxygenated blood to the upper limb Median nerve = Largest branch of the brachial plexus, responsible for innervating finger extension and sensation Biceps tendon = Thick cord-like structure connecting biceps brachii muscle to the radius bone Penetrating injuries = Injuries, particularly involving sharp objects, that can potentially damage the biceps tendon Signup and view all the answers

Match the following upper limb components with their functions:

Brachial artery = Provides oxygenated blood to maintain muscle function and tissue health in the upper limb Median nerve = Innervates muscles for finger extension and provides sensation to specific fingers Biceps tendon = Facilitates elbow flexion and wrist supination Penetrating injuries = Can potentially damage the biceps tendon in the forearm Signup and view all the answers

Match the upper limb anatomy component with its location in the body:

Brachial artery = Runs down the upper arm until it divides into radial and ulnar arteries just above the elbow joint Median nerve = Travels along the posterior side of the biceps muscle in the upper arm and passes under the ligament of Struthers to enter the forearm Biceps tendon = Connects the biceps brachii muscle to the radius bone in the forearm Penetrating injuries = Can potentially damage the biceps tendon, located in the forearm Signup and view all the answers

Match the following upper limb anatomy components with their primary roles:

Brachial artery = Provides oxygenated blood to maintain muscle function and tissue health in the upper limb Median nerve = Innervates muscles responsible for finger extension and provides sensation to specific fingers Biceps tendon = Facilitates elbow flexion and wrist supination Penetrating injuries = Can potentially damage the biceps tendon, affecting its primary function Signup and view all the answers

Match the upper limb structures with their significance in penetrating injuries:

Brachial artery = Vessel that can be affected by penetrating injuries in the upper arm Median nerve = Nerve susceptible to damage in penetrating injuries involving sharp objects Biceps tendon = Structure that can be harmed in penetrating injuries affecting the forearm Penetrating injuries = 'Can potentially cause damage to various structures such as nerves, blood vessels, and tendons Signup and view all the answers

Study Notes

Pectoral Girdle

Composed of two bones: clavicle and scapula
Clavicle:
- S-shaped bone
- Articulates with sternum proximally and scapula distally
- Only bony attachment of the upper limb to the axial skeleton
- First long bone to start ossification (week 5-6) and last to fuse (22-25 years)
- Scale-like ossification center at the sternal end
Scapula:
- Resembles a small shovel
- Provides stability and support for the upper limbs
- Key features:
  - Acromion: outermost projection of the spine at the end of the collarbone
    - Point of attachment for several muscles (trapezius, etc.)
    - Provides protection against blows to the head or neck
  - Coracoid process: hook-like extension near the top of the shoulder blade
    - Attachment site for muscles (pectoralis major, serratus anterior)
  - Glenoid cavity: shallow depression on the ventral side of the scapula's spine
    - Articulating region where the humerus bone fits into place during arm movement
    - Surrounded by ligaments for extra stability

Shoulder Girdle

Consists of two main bones: clavicle and scapula
Connects the axial skeleton (head, trunk, arms) to the appendicular skeleton (upper limb)
Key joints:
- Sternoclavicular joint: articulation between the clavicle and sternum
- Acromioclavicular joint: articulation between the clavicle and acromion of the scapula
- Glenohumeral joint: articulation between the humerus and glenoid cavity of the scapula
Ligaments and muscles stabilize the joints

Humerus

Single bone of the arm
Head of the humerus articulates with the glenoid fossa of the scapula
Key features:
- Proximal end:
  - Anatomical neck
  - Lesser tubercle (anteriorly)
  - Greater tubercle (laterally)
  - Intertubercular (bicipital) groove (on the anterior side)
- Distal end:
  - Capitulum (for articulation with the radius of the forearm)
  - Trochlea (for articulation with the ulna)
  - Radial fossa and coronoid fossa (anteriorly)
  - Olecranon fossa (posteriorly)
- Medial and lateral epicondyles
- Supracondylar ridges
- Radial groove (on the medial aspect of the humerus)

Blood Supply and Innervation

Axillary artery and vein
Brachial plexus:
- Extends from the neck to the axilla
- Supplies the upper limb
- Composed of roots, trunks, divisions, cords, and branches
- Dermatomes of the brachial plexus:
  - C5: lateral side of the forearm and thumb
  - C6: skin of the neck, shoulder, inner aspect of the biceps, and ulnar half of the forearm
  - C7: deltoid, axilla, and lateral epicondyle of the humerus### Limb Structure
Superficial fascia layer directly beneath the skin
Deep fascia layer surrounding deep structures, including muscles, nerves, and arteries
Perivascular sheath containing major nerves and arteries
Intermuscular septa dividing limbs into compartments, separating groups of muscles

Compartment Syndrome

Deep fascia not expansible, leading to pressure buildup and ischaemia
Compression of low-pressure blood vessels and nerves causing tingling and numbness
Ischaemia leading to muscle damage and swelling
Untreated compartment syndrome leading to tissue death
Fasciotomy used to relieve pressure and prevent further damage

Biceps Brachii Muscle

Two heads (long and short) arising from scapula and coracoid process
Insertion on radial tuberosity, with bicipital aponeurosis in medial forearm
Functions as a flexor at the elbow and shoulder joints
Weak flexor at the shoulder, powerful flexor and supinator at the elbow

Anterior Compartment Muscles

Brachialis muscle arising from anterior humerus, inserting on ulnar tuberosity
Coracobrachialis muscle running from coracoid process to medial humerus
Flexes and adducts the arm at the glenohumeral joint

Nerves of the Upper Extremity

Musculocutaneous nerve arising from lateral cord of brachial plexus
Innervates coracobrachialis muscle, then travels between biceps and brachialis muscles
Emerges lateral to biceps tendon at the elbow, becoming lateral antebrachial cutaneous nerve
Median and ulnar nerves have no branches in the arm

Blood Vessels

Brachial artery passing through the elbow, dividing into radial and ulnar arteries
Profunda brachii (deep brachial artery) branching off from the brachial artery
Radial artery remaining superficial, ulnar artery going deep

Neurovascular Bundle

Median and ulnar nerves, and brachial artery in close proximity on the medial side of the arm
Brachial pulse can be palpated at this location

Venous System

Deep veins accompanying major arteries, venae comitantes
Superficial veins running independently in the superficial fascia, important for thermoregulation
Superficial veins becoming more prominent when deep veins are compressed

Cubital Fossa

Triangular region marked by the epicondyles and the borders of the pronator teres and brachioradialis muscles
Containing superficial veins, cutaneous nerves, and the biceps tendon and bicipital aponeurosis

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Description

Moritz Block 4 Week 2

Shoulder, upper arm, and brachial plexus

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Questions and Answers

What is the significance of the clavicle in the human body?

At what age does the scale-like ossification center at the sternal end of the clavicle begin to fuse with the diaphysis?

Which bone in the human body is the first long bone to begin ossification?

During skeletal development, what can the fusion of the clavicle be mistaken for?

Which bone does the clavicle articulate with proximally and distally?

Which part of the scapula acts as an attachment site for the trapezius muscle?

What is the primary function of the coracoid process on the scapula?

Where is the glenoid cavity located on the scapula?

How many main bones make up the shoulder girdle?

Which part of the skeletal structure connects the axial skeleton to the appendicular skeleton?

Which part of the humerus is more commonly associated with fractures?

Where is the deltoid tuberosity located in relation to the humerus head?

Which part of the humerus is commonly referred to as a 'bump'?

In the anatomy of the humerus, which part separates the greater and lesser tubercles?

Which part of the humerus is most proximal?

What type of joint is the sternoclavicular joint?

Which structure divides the sternoclavicular joint into two compartments?

Where does the clavicle articulate with the scapula?

Which joint allows movements of the shoulder girdle?

Why is the glenoid cavity considered shallow in the shoulder joint?

Which ligament is responsible for shoulder stability by connecting the acromion and the clavicle?

Which joint in the shoulder region is susceptible to dislocation when falling on an outstretched arm?

What type of joint is the acromioclavicular joint?

In a complete shoulder separation injury, which ligaments are ruptured?

What is the common outcome of a fall capable of separating the AC joint?

What structure deepens the glenoid cavity in the shoulder joint?

Which ligament plays a role in stabilizing the shoulder joint by connecting the acromion and the coracoid process?

Which structure separates the supra and infraspinatus muscles from the acromion and coracoacromial ligament?

Which type of joint is the glenohumeral joint in the shoulder region?

Which anatomical feature in the shoulder provides attachment for the trapezius muscle?

What is the primary function of the acromion in the shoulder joint?

In which type of shoulder dislocation does the humeral head often end up in a subcoracoid location?

What is the structure on the scapula that serves as an attachment site for the trapezius muscle?

Which part of the shoulder girdle is responsible for connecting the axial skeleton to the appendicular skeleton?

Why are shoulder dislocations, particularly anterior dislocations, more common in patients younger than 30 years?

Which muscle originates from the spine of the scapula, acromion, and lateral 1/3 of the clavicle to insert on the deltoid tuberosity of the humerus?

Which nerve innervates the deltoid muscle responsible for abducting the arm?

Which structure on the scapula serves as an attachment point for the trapezius muscle?

What function does the acromion serve in the shoulder joint?

Where does the deltoid tuberosity attach on the humerus in relation to the humeral head?

Which structure originates from the anterior surface of the scapula and inserts on the lesser tubercle of the humerus?

What nerve innervates the teres minor muscle, which is a lateral rotator located deep to the deltoid muscle?

In the shoulder girdle, which muscle is primarily responsible for initiating the first 15 degrees of abduction?

Which muscle, innervated by the suprascapular nerve, is a lateral (external) rotator of the humerus?

Which muscle, originating from the posterior surface of the scapula, provides stability to the glenohumeral joint?

Which muscle is most vulnerable to injury due to repeated abduction and flexion?

What is the primary function of the acromion in relation to the shoulder joint?

Where does the teres major muscle originate from?

Which structure forms a musculotendinous cuff around the shoulder joint?

What causes pain in the supraspinatus (impingement) syndrome between 60 and 120° of abduction?

Which muscle originates from the infraglenoid tubercle and passes anterior to the teres minor but posterior to the teres major?

Which muscle provides stability to the glenohumeral joint by connecting the acromion to the humerus?

Which structure creates borders for the triangular space in the shoulder, allowing structures to pass through?

What is the primary function of the acromion within the shoulder joint anatomy?

Which part of the humerus separates the greater tubercle from the lesser tubercle?

Through which space do the radial nerve and deep artery of the arm pass?

What mnemonic is used to remember that the artery is superficial and the nerve is deep to the transverse scapular ligament?

Which vessels provide collateral circulation to the upper limb if the proximal part of the axillary artery becomes occluded?

Which structures supply both the supra- and infraspinatus muscles?

What do the axial rich vascular anastomoses around the shoulder joint primarily supply?

Which muscle retracts and medially rotates the scapula?

Where does the trapezius muscle insert?

Which nerve innervates the latissimus dorsi muscle?

What is the primary function of the coracoid process on the scapula?

Which structure deepens the glenoid cavity?

Which muscle is primarily responsible for protracting and laterally rotating the scapula?

Injury to which nerve can lead to the clinical presentation of 'winged scapula'?

What is the primary function of the acromion in relation to the shoulder joint?

Which structure on the scapula serves as an attachment point for the deltoid muscle?

What can cause injury to the long thoracic nerve leading to 'winged scapula'?

What nerve innervates the levator scapulae muscle, which attaches to the transverse processes of the upper cervical vertebrae and elevates the scapula?

Which artery changes its name to the axillary artery at the lateral border of the first rib and continues through the axilla to the inferior border of the teres major muscle?

In the shoulder region, where does the subclavian artery change its name to the axillary artery?

Which muscle primarily elevates the scapula by attaching to the superior angle of the scapula and providing attachment to the posterior rib cage?

What structure separates the greater tubercle from the lesser tubercle on the humerus?

What is the primary function of the acromion in the shoulder joint?