Movement Science Week 5

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Questions and Answers

What type of joint allows for greater stability at the intersection between the appendicular and axial skeleton?

Plane joint

Hinge joint

Saddle joint (correct)

Ball and socket joint

In which plane of motion does protraction and retraction occur?

Sagittal plane

Frontal plane (correct)

Transverse plane

None of the above

What occurs simultaneously when the clavicle is elevated?

Inferior roll with superior slide

Superior roll with superior slide

Inferior roll with inferior slide

Superior roll with inferior slide (correct)

What is the primary kinematic motion of the acromioclavicular joint?

Upward and downward rotation Signup and view all the answers

What type of motion primarily occurs at the scapulothoracic joint?

Elevations and depressions Signup and view all the answers

What is the approximate ratio of glenohumeral joint motion to scapulothoracic joint motion after the initial 30 degrees of shoulder abduction?

2 to 1 Signup and view all the answers

What anatomical structure's size mismatch contributes to instability in the glenohumeral joint?

Humeral head Signup and view all the answers

What happens to the humeral head during shoulder abduction?

It rolls superiorly and slides inferiorly. Signup and view all the answers

Which condition may result from inadequate inferior slide of the humeral head during overhead activities?

Impingement syndrome Signup and view all the answers

After how many degrees of shoulder abduction does the scapulohumeral rhythm describe the 2 to 1 motion ratio?

30 degrees Signup and view all the answers

What characterizes the humeroulnar joint in terms of movement?

It functions with slight side-to-side motion as a modified hinge joint. Signup and view all the answers

In the context of elbow joint movement, what does full extension require?

Sufficient extensibility of the anterior structures, including the anterior capsule. Signup and view all the answers

What type of motion occurs at the proximal radio-ulnar joint during supination?

Pure rotation occurs without a slide due to the annular ligament. Signup and view all the answers

Which statement about the motion of the ulna during closed chain pronation is true?

The radius remains stationary while the ulna rotates around it. Signup and view all the answers

What distinguishes pronation and supination in terms of anatomical positioning?

Pronation involves the radius rotating over the ulna. Signup and view all the answers

What is the main role of the infraspinatus during external rotation of the shoulder?

To cause the humeral head to roll posteriorly and slide anteriorly Signup and view all the answers

Which joints are part of the elbow and forearm complex?

Humeroradial joint, proximal radio-ulnar joint, distal radio-ulnar joint, humeroulnar joint Signup and view all the answers

How does the configuration of the head of the ulna affect the distal radio-ulnar joint?

It influences the arthrokinematic motion at the joint Signup and view all the answers

How many bones make up the shoulder complex?

Five Signup and view all the answers

What distinguishes the elbow joint from a traditional hinge joint?

It has a significant axial rotation during flexion and extension Signup and view all the answers

Where is the fovea located and what is its significance?

Within the head of the radius, articulating with the concave capitulum of the humerus Signup and view all the answers

Which joint is not considered a true joint in the shoulder complex?

Scapulothoracic joint Signup and view all the answers

Which joint involves the articulation between the sternum and the clavicle?

Sternoclavicular joint Signup and view all the answers

What types of motion occur at the scapulothoracic joint?

Only osteokinematic motion Signup and view all the answers

Which of the following joints is directly linked to the shoulder complex's arthrokinematic motion?

Acromioclavicular joint Signup and view all the answers

What role does the annular ligament play at the proximal radio-ulnar joint during rotation?

It prevents a concomitant slide during rotation. Signup and view all the answers

During supination of the forearm, what movement occurs at the distal radio-ulnar joint?

A roll and slide occur in opposite directions. Signup and view all the answers

What happens to the ulna when the hand is fixed to a surface during pronation?

The ulna rotates around the fixed radius. Signup and view all the answers

Which of the following statements about the humeroradial joint is true?

It has a vertical axis of rotation resulting in a horizontal plane motion. Signup and view all the answers

What allows for the wrist to exhibit greater extensibility in its motions?

The combined functions of the radio-carpal and mid-carpal joints. Signup and view all the answers

What is the primary reason for having more range of motion during ulnar deviation compared to radial deviation?

The ulnar tilt allows for greater movement toward the ulna. Signup and view all the answers

Which carpal bone is most commonly dislocated, and why?

Lunate; because it lacks muscular attachments. Signup and view all the answers

What anatomical feature is important for distinguishing the extensor carpi radialis brevis tendon from the extensor pollicis longus tendon?

The tubercle on the radius. Signup and view all the answers

How many degrees of wrist flexion are typically available compared to wrist extension?

80 degrees of flexion and 70 degrees of extension. Signup and view all the answers

Which carpal bone is described as having a shape related to a boat?

Scaphoid Signup and view all the answers

What percentage of forces through the carpal bones runs through the radial side of the radiocarpal joint?

80% Signup and view all the answers

What is the role of the capitate bone in the wrist structure?

It provides longitudinal stability to the wrist. Signup and view all the answers

Which movement occurs when the lunate rolls dorsally on the radius during wrist extension?

Palmar slide Signup and view all the answers

What differentiates the trapezium from the trapezoid in the wrist anatomy?

The trapezium is larger and has an asymmetric shape. Signup and view all the answers

What happens to the capitate bone during wrist flexion?

It rolls palmarly and slides dorsally. Signup and view all the answers

Study Notes

Shoulder Complex Overview

The shoulder complex comprises five bones: humerus, clavicle, scapula, sternum, and ribs.
It encompasses four main joints:
- Glenohumeral joint
- Acromioclavicular (AC) joint
- Sternoclavicular (SC) joint
- Scapulothoracic joint (not a true joint, an interface between the thorax and scapula).

Joint Characteristics

Sternoclavicular Joint:
- Unique saddle joint allowing stability between the appendicular and axial skeleton.
- Extensive periarticular connective tissue enhances attachment strength.
Clavicle's Movements:
- Exhibits three degrees of freedom: elevation/depression, protraction/retraction, and rotation.
- Elevation causes a superior roll and inferior slide due to its convex shape.

Acromioclavicular Joint

Articulates between distal clavicle and acromion of the scapula.
Functions as a planar joint allowing gliding movements.
Main function is to optimize movement rather than increasing range of motion.
Primary motion includes upward/downward rotation; secondary motions involve rotational adjustments.

Scapulothoracic Joint

Not a true joint; significant for movements like elevation/depression, adduction/abduction, and rotation.
In shoulder elevation (shrug), SC joint elevates while the AC joint undergoes downward rotation to maintain scapula alignment.

Scapulohumeral Rhythm

Describes the coordinated movement required between scapulothoracic and glenohumeral joints during shoulder abduction.
A 2:1 ratio of motion exists after the first 30 degrees of abduction.

Glenohumeral Joint Characteristics

Demonstrates a large size mismatch, leading to extensive range of motion but increased instability.
The humeral head is significantly larger than the glenoid fossa, comparable to a golf ball on a quarter.

Kinematic Analysis

Movements at the glenohumeral joint have three degrees of freedom.
Abduction involves a superior roll and inferior slide, vital to prevent impingement syndrome.
Flexion and extension of the joint involve simple rotation, while internal/external rotation involve complex movements influenced by muscle actions.

Elbow and Forearm Complex Overview

Comprised of three bones: humerus, radius, and ulna.
Consists of four joints:
- Humeroradial joint
- Humeroulnar joint
- Proximal radioulnar joint
- Distal radioulnar joint.

Elbow Joint Features

Features the trochlea and capitulum of the humerus for ulna and radius articulation respectively.
Tight fits created by the trochlea's medial and lateral lips enhance stability.

Ulna and Radius Anatomy

Olecranon process is a key feature of the ulna, while the radius includes a concave fovea on its head for articulation with the capitulum.
Pronation and supination involve the radius rotating over the ulna, facilitated by the pronator quadratus and supinator muscles.

Joint Mechanics

The elbow is classified as a modified hinge joint allowing primarily flexion and extension with limited rotational ability.
Forearm movements involve complex interactions between the radius and ulna based on the position and stability of the wrist and elbow.### Elbow Joint Kinematics
The elbow is classified as a modified hinge joint due to slight axial rotation and side-to-side motion occurring during flexion and extension.
Composed of the humeroulnar and humeroradial joints, proper extensibility of anterior structures is required for complete elbow extension.
Flexion involves a simultaneous roll and slide of the ulna's concave trochlear notch on the convex trochlea of the humerus.
Humeroradial joint has similar kinematics, with the concave fovea of the radius articulating against the convex capitulum of the humerus.

Forearm Rotation

The forearm features proximal and distal radio-ulnar joints, facilitating pronation and supination in the horizontal plane.
Independent hand rotation is possible without mandatory ulna or humerus rotation due to the stable link between the ulna and humerus at the humeroulnar joint.
Supination aligns the radius and ulna, while pronation rotates the radius over the ulna.
In closed-chain positions, ulna motion triggers external rotation at the humerus during pronation, and internal rotation during supination.

Proximal and Distal Radio-Ulnar Joint Mechanics

At the proximal radio-ulnar joint, rotation occurs without translation due to the annular ligament's constraints.
The distal radio-ulnar joint permits both motion and a roll-slide mechanism, maintaining concave and convex surfaces' interaction during supination and pronation.

Arthrokinematics of the Humeroradial Joint

The humeroradial joint experiences significant pronation and supination movement, vital for everyday activities.
Compression torque from muscle activation can lead to greater degeneration at the humeroradial joint compared to the humeroulnar joint.
The vertical axis of rotation at the humeroradial joint allows for a spin within the horizontal plane.

Wrist Structure and Function

The wrist, or carpus, comprises eight carpal bones organized into proximal and distal rows, housing three primary joints: the distal radial-ulnar joint, radiocarpal joint, and mid-carpal joint.
The distal radial-ulnar joint allows for wrist stability with an ulnar tilt providing greater range in ulnar deviation compared to radial deviation.

Carpal Bones Overview

Proximal row includes scaphoid, lunate, triquetrum, and pisiform; distal row features trapezium, trapezoid, capitate, and hamate.
Scaphoid shaped like a boat, crucial for joint formation and articulation with several bones, is highly vascularized but prone to fracture.
Lunate is the most commonly dislocated carpal bone due to the absence of muscular attachments and weaker ligaments.
The capitate serves as a central pillar of the wrist, articulating with multiple bones and providing stability.

Wrist Mechanics

A fall on an outstretched hand primarily transmits force through the radius rather than the ulna, highlighting the importance of the radiocarpal joint in shock absorption and stability during impact.### Carpal and Radiocarpal Joint Mechanics
Approximately 80% of forces through the carpal bones travel through the radial side of the radiocarpal joint, while about 20% run through the ulnar side.
Most fractures at the radiocarpal joint occur at the radius due to the majority of force transmission through it.
The radiocarpal joint can be divided into medial (ulnar) and lateral compartments, which have differing arthrokinematic properties.
Capitate bone serves as the axis for all wrist motion, facilitating flexion, extension, and both ulnar and radial deviation.

Wrist Movement Dynamics

Motion in the wrist includes flexion and extension around the anterior-posterior axis and ulnar and radial deviation around the medial-lateral axis.
Wrist allows minimal axial rotation, raising questions about its rotational capabilities.
Arthrokinematics involve coordinated movement between the radiocarpal and midcarpal joints, allowing for greater flexibility.

Radiocarpal Joint Movement

During extension: the convex lunate rolls dorsal (back) and slides palmar (forward) on concave radius.
During flexion: lunate rolls palmar and slides dorsal against the radius.
Similar coordinated movement of the capitate occurs with the lunate, emphasizing collective movement rather than isolated joint motion.

Ulnar and Radial Deviation

Effective radial deviation is limited due to scaphoid bone colliding with the styloid process of the radius, with about 85% occurring at the midcarpal joint.
Ulnar deviation results in an ulnar roll and radial slide, whereas radial deviation causes a radial roll and ulnar slide.

Hand Anatomy Overview

Fingers are identified as digits 1 through 5, starting with the thumb, which has a unique joint structure: one IP joint compared to the two in other fingers.
Key joints include carpometacarpal (CMC), metacarpophalangeal (MCP), and interphalangeal (IP) joints, often referred to by acronyms CMC, MCP, DIP, and PIP respectively.

Tunnel-like Structure of the Hand

The hand exhibits a concave shape with two transverse arches and one longitudinal arch, enhancing grip and functionality.
The capitate acts as a keystone for the proximal transverse arch, facilitating stability at the CMC joints.

Finger Movements

Flexion and extension bring fingers together or move them apart; abduction increases distance between fingers, while adduction decreases it relative to the third ray.
Thumb movements differ, with abduction occurring away from the palm and opposition allowing for interaction with the fingers.

Arthrokinematics of the Thumb

CMC joint of the thumb is a saddle joint these movements include abduction (roll anterior, slide posterior) and flexion/extension (roll and slide in the same direction).
The IP joint of the thumb behaves similarly to the finger joints but with unique mechanics due to its single structure.

Interphalangeal Joints

The proximal and distal IP joints of the fingers allow for flexion and extension, with minimal rotation due to central ridges and constraints from collateral ligaments.
Thumb contains one IP joint characterized by similar roll and slide arthrokinematics.

Pelvic Anatomy and Kinematics

The pelvis is comprised of ilium, pubis, and ischium, connecting the femoral head to the acetabulum.
Anterior superior iliac spine (ASIS) serves as a prominent landmark for palpation, critical for understanding posture and pelvic mechanics.

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Description

This quiz explores the functional aspects of wrist anatomy, focusing on the mechanics of radial and ulnar deviation. It covers the role of the capitate bone and the proximal carpal row in wrist motion. Perfect for students studying human anatomy or physical therapy.

Movement Science Week 5 - Transcripts

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