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Mostración Cadavérica 202 - Carpo y Mano
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Mostración Cadavérica 202 - Carpo y Mano

Introduction to Anatomy of the Hand

The video introduces the anatomy of the hand, focusing on bones and joints in the carpal and metacarpal regions.

Bones and Joints Overview

  • The video covers the bones and joints of the carpal region, including the scaphoid, lunate, pyramidal, pisiform, trapezium, trapezoid, capitate, and hamate.
  • Detailed description of bone locations in the hand preparation is provided: distal epiphysis of radius and ulna, lateral carpal bones, fifth metacarpal bone.
  • Explanation of anatomical positions for understanding references like superior/inferior/medial/lateral in describing carpal bones.
  • Identification of carpal bones in two rows: proximal (scaphoid, lunate, triquetrum, pisiform) and distal (trapezium, trapezoid, capitate, hamate).

Bone Structure Details

  • Discussion on short bones' characteristics: length-width-thickness dimensions; support function; non-articular prominences and articulating surfaces.
  • Emphasis on non-articular prominences like tubercle of scaphoid; dorsal/palmar faces; first metacarpal articulation.

Anatomy Lecture Insights

In this section, the speaker discusses the anatomy of the carpal bones, focusing on their articulations and specific features.

Articulation of Carpal Bones

  • The scaphoid, lunate, and triquetrum articulate to form the carpal joint.
  • These bones contribute to the proximal convexity of the joint.
  • The pisiform bone articulates solely with the pyramidal bone.
  • This articulation occurs on the palmar side with the pyramidal bone's anterior face.
  • Understanding these articulations is crucial due to gender-specific variations in joints.
  • Gender differences impact joint characteristics.

Sesamoid and Intra-tendinous Bones

  • Carpals can be classified into sesamoid and intra-tendinous types.
  • Sesamoid bones are periarticular while intra-tendinous bones develop within tendons.
  • The pisiform was historically considered a sesamoid or intra-tendinous bone due to its location within tendons.
  • It inserts into the flexor carpi ulnaris muscle.

Trapezium and Trapezoid Bones

  • The trapezium is larger than the trapezoid in the second row of carpal bones.
  • It features structures like tubercles on its anterior-lateral side for ligament attachments.
  • The trapezoid has non-articular surfaces for ligaments on its palmar and dorsal sides.
  • It presents distinct eminences for articulation with adjacent metacarpals.

Capitate Bone Characteristics

  • The capitate bone has three main parts: head, neck, and body.
  • Its superior convexity adapts to fit concavities in neighboring bones like the scaphoid.

Triquetrum Bone Details

  • The triquetrum has medial and lateral articular surfaces for adjoining carpal bones in its second-row position.

New Section

In this section, the speaker discusses the anatomy of the hand, focusing on the metacarpal bones and their articulations.

Metacarpal Bones and Their Articulations

  • The superior aspect of the metacarpal bones features a convexity for the carpal tunnel and an articular surface for intercarpal joints.
  • Each metacarpal bone has a lateral articular face for intermetacarpal joints.
  • The first metacarpal bone has a distal articular face for the fifth metacarpal bone.

New Section

This part delves into the semilunar bone, third metacarpal bone, and phalanx classification in hand anatomy.

Semilunar Bone and Phalanx Classification

  • The semilunar bone articulates with the trapezium.
  • The third metacarpal bone is discussed along with phalanx types: proximal, middle, and distal.

New Section

Here, the focus shifts to defining movements in relation to hand anatomy axes.

Hand Anatomy Axes and Movements

  • Movements like adduction and abduction are defined based on specific hand axes rather than central body axes.

New Section

This segment elaborates on metacarpal bones' characteristics compared to carpal bones.

Metacarpal Bones Characteristics

  • Metacarpals are enumerated from lateral to medial: first to fifth.
  • Metacarpals differ from carpal bones as they are long bones with diaphysis, epiphysis, and metaphysis regions.

New Section

Detailed descriptions of individual metacarpals' unique features are provided in this part.

Individual Metacarpi Characteristics

  • The first metacarpal is the shortest in length among all metacarpals.
  • Intermetacarpian joints articulate between adjacent metarcapals through specific surfaces.

Articulations of the Carpal Bones

In this section, the articulations between the carpal bones are discussed, focusing on how the bones in the first row articulate with each other and with those in the second row.

Articulations of the First Row

  • The articulations in the first row are known as intercarpal joints.
  • These joints occur between the medial or lateral faces of the bones, depending on which bone is being discussed.
  • Example: The medial articular face of one bone articulates with the lateral articular face of another bone.

Specific Articulations

  • The medial articular face of the semilunar bone articulates with the lateral articular face of the pyramidal bone, forming an intercarpal joint.
  • There are two specific intercarpal joints in the first row that connect three bones.

Types and Surfaces of Articulations

This section delves into specific types and surfaces of articulations within carpal bones, highlighting synovial joints and their characteristics.

Types of Joints

  • The intercarpal joints in the proximal row are synovial joints with a planar type of tissue interposed.
  • These planar joints occur when one bone's surface articulates with another's anterior face.

Surface Characteristics

  • An ellipsoid-type joint exists between scaphoid and pyramidal bones due to their unique articular surfaces.
  • The anterior face of pyramidal bone has a slight convexity while its dorsal side has a slight concavity, forming an ellipsoid joint.

Articulations in Second Row

This part focuses on articulations within carpal bones' second row, emphasizing interactions between trapezium, trapezoid, capitate, and hamate bones.

Interactions in Second Row

  • Three intercarpal joints exist between trapezium-trapezoid, trapezoid-capitate, and capitate-hamate bones.
  • Each interaction involves medial or lateral articular faces connecting these bones together.

Midcarpal Joint Structure

Discusses midcarpal joint structure involving synovial type joints categorized as ellipsoid or condyloid based on surface configurations.

Midcarpal Joint Details

  • The midcarpal joint connects both rows through a synovial joint classified as ellipsoid or condyloid.

Detailed Analysis of Hand Articulations

In this section, the speaker delves into the intricate details of hand articulations, focusing on the metacarpophalangeal joints and interphalangeal joints.

Metacarpophalangeal Joint Structure

  • The articulation between the metacarpus and proximal phalanx lacks complete correspondence in articular surfaces.
  • The head of the metacarpal bone extends anteriorly beyond the glenoid cavity of the proximal phalanx, necessitating the insertion of a fibrocartilage ligament known as the palmar ligament.

Thumb Articulation Specifics

  • The joint between the first metacarpal head and proximal phalanx of the thumb features sesamoid bones on both sides, distinguishing it from other metacarpophalangeal joints.
  • Contrary to earlier beliefs about intra-tendinous bones in upper limbs, certain hand articulations exhibit sesamoid bones like those found in thumb joints.

Interphalangeal Joints and Ligaments

  • Ligaments such as the palmar ligament are present in interphalangeal joints, aiding in joint stability.
  • Interphalangeal joint surfaces do not align entirely, requiring support from structures like the palmar ligament for proper function.

Thumb vs. Other Finger Joints

  • Notable differences exist between thumb and other finger metacarpophalangeal joints regarding ligament connections and sesamoid bone presence.

Anatomy Lecture on Articulations of the Wrist and Hand

In this section, the lecturer discusses the articulations of the wrist and hand, focusing on specific bones and ligaments involved in these joints.

Carpian Joint Structures

  • The term "carpiano" refers to the convex surface of three named bones.
  • Differentiating between the carpian joint and other structures like condylar carpiano.

Articulation Details

  • Describing the relationship between the lunate bone and pyramidal bone.
  • Identifying specific carpal bones such as second, third, fourth, and fifth metacarpals.

Ligamentous Structures

  • Discussing ligamentous fascicles related to the ulnar collateral ligament at the radiocarpal joint.
  • Explaining how ligaments attach to different carpal bones like pisiform and hook of hamate.

Continuation: Anatomy Lecture on Wrist Articulations

This part delves deeper into wrist articulations, highlighting movements, ligaments, and joint structures.

Radioulnar Joint Movements

  • Detailing movements from radial head to ulnar head during pronation-supination actions.
  • Explaining how ligaments contribute to stabilizing these movements within the joint.

Radio-cubital Distal Joint

  • Describing this simple synovial joint formed by two bones for flexion-extension actions.
  • Analyzing articular surfaces for pronation-supination motions in this distal radio-cubital joint.

Muscles of Hand: Anatomical Description

Transitioning into a discussion on hand muscles categorization based on regions within the hand anatomy.

Muscle Groupings

  • Categorizing hand muscles into three main groups: thenar region, hypothenar region, and midregion.
  • Identifying muscle locations based on superior-inferior or lateral-medial orientations within hand anatomy.

New Section

In this section, the speaker discusses the anatomy of the flexor muscles in the hand, focusing on the flexor pollicis brevis.

Flexor Pollicis Brevis Anatomy

  • The flexor pollicis brevis consists of superficial and deep fascicles. The superficial fascicle originates from the trapezium bone and inserts into the base of the proximal phalanx of the thumb.
  • The deep fascicle may vary in presence and innervation; it typically arises centrally to insert at similar locations as the superficial fascicle.
  • Innervation of the superficial fascicle is through the median nerve, specifically its thenar branch. However, if a deep fascicle is present, it is often innervated by the ulnar nerve.
  • Blood supply to these muscles includes branches from the radial artery, similar to other hand muscles like abductor pollicis brevis.

New Section

This part delves into details about another muscle group in hand anatomy: adductor pollicis.

Adductor Pollicis Muscle Structure

  • The adductor pollicis muscle comprises transverse and oblique heads. The transverse head originates from the third metacarpal's lateral aspect and inserts into the base of the proximal phalanx of thumb.
  • Conversely, the oblique head arises from various carpal bones (trapezoid, capitate) and metacarpals (1st to 3rd) before inserting similarly at thumb's base.
  • Innervation for this muscle comes from ulnar nerve branches while blood supply involves branches from ulnar artery.

Anatomy of Hand Muscles

In this section, the speaker delves into the detailed anatomy of hand muscles, focusing on the lumbrical muscles and their functions.

Lumbrical Muscles Anatomy

  • The lumbrical muscles are located in the lateral anterior aspect of the forearm.
  • These muscles extend distally towards the metacarpophalangeal joint, inserting at the base of the proximal phalanx and associating with interosseous muscles.
  • Each lumbrical muscle corresponds to a specific finger: index, middle, ring, or little finger.
  • Lumbricals 3 and 4 originate from two tendons each, while 1 and 2 have a single tendon origin.
  • Innervation differs among lumbricals; digits 2 and 3 are innervated by the median nerve, while digits 3 and 4 are innervated by the ulnar nerve.

Continuation of Hand Muscles Description

This part continues exploring hand muscle anatomy with a focus on palmar interossei muscles.

Palmar Interossei Muscles

  • Returning to the initial preparation for hand muscle examination.
  • To understand palmar interossei insertion points, knowledge of hand axis alignment is crucial.
  • Palmar interossei typically insert distally in relation to their corresponding fingers' metacarpals.
  • Specific examples include abductor pollicis brevis originating from thumb metacarpal bone and inserting at thumb base.

Detailed Examination of Dorsal Interossei Muscles

The discussion shifts to dorsal interossei muscles' examination and function within hand anatomy.

Dorsal Interossei Muscles

  • Dorsal interossei lie dorsally when tendons are separated from flexor muscles.
  • Dorsal interossei differ from palmar ones as they direct towards fingers farthest from hand axis.

New Section

In this section, the speaker discusses the anatomy of the hand and fingers, focusing on specific structures and their relationships.

Anatomy of Hand and Fingers

  • The deep fascicle directs towards the base of the proximal phalanx of the ring finger, emphasizing proximity to the nearest phalangeal base. This differs for the pinky and index fingers.
  • Innovative aspects include vital dorsal metacarpal arteries. Muscles in this region function to flex the proximal phalanx, extend genital areas, and separate middle finger from other digits.
  • Nerve elements in carpal and hand regions are described concerning lateral, distal (inferior), medial (entering pinky), and superior (forearm connection).
  • The median nerve originates vertically in the forearm, traverses through carpal tunnel to palm's center, branching into various terminals including thumb abductor and short flexor muscles.

New Section

The discussion focuses on the division of nerves in a radial scenario, detailing the formation of digital dorsal lateral nerves.

Nerve Division and Formation

  • The nerve division occurs in this radial scenario, with branches splitting into lateral and medial rami.
  • Specific nerves are marked for identification, such as the digital dorsal lateral nerve of the thumb and index finger.
  • Description begins with the artery's role in relation to vascular elements, starting from the middle sector of the forearm.
  • Arteries like the palmar branch of the ulnar artery continue their descent, branching into dorsal carpal arteries.
  • Further branching leads to deep arterial structures forming an arch within deeper planes.

New Section

This segment delves into arterial branching patterns and anastomoses within hand vasculature.

Arterial Branching and Anastomoses

  • Arteries form superficial arches through anastomoses between radial and ulnar branches.
  • Detailed descriptions include specific arteries like the first common digital artery continuing as digital arteries for individual fingers.
  • The pattern continues with divisions into palmar arteries for different fingers, emphasizing distinct pathways for each digit.

New Section

Vascularization details progress towards describing radial artery anatomy in hand regions.

Radial Artery Description

  • The radial artery's trajectory is traced from forearm to wrist regions, highlighting its course towards carpal areas.
  • Branching patterns lead to specific digital arteries supplying various fingers individually.

New Section

Anatomical landmarks are identified concerning finger positions and corresponding arterial paths.

Finger Positioning and Arterial Identification

  • Finger positioning aids in locating specific arteries related to radial nerve distribution within hand regions.

New Section

In this section, the speaker discusses the deep tendons in the hand, focusing on specific muscles and arteries.

Deep Tendons and Arteries

  • The speaker identifies the deep tendons of the extensor muscles in the hand, specifically highlighting the extensor tendons of the radial muscles.
  • Arteries branching off to supply different regions are discussed, including the main artery for thumb irrigation and a dorsal carpal artery for dorsal hand region nourishment.
  • Details about a significant artery responsible for dorsal hand region irrigation are provided, emphasizing its size and potential connections with other arteries like the dorsal ulnar artery.

Next Topic Title

This part delves into topographical aspects of the hand region, outlining key landmarks and orientations.

Topographical Orientation

  • The speaker explains how to identify superior, inferior, lateral, and medial positions in relation to various structures in the hand.
  • Landmarks such as the ulnar head and cubital fossa aid in delineating boundaries for understanding carpal regions effectively.

Further Exploration

The discussion shifts towards exploring critical anatomical features within the carpal tunnel area.

Carpal Tunnel Anatomy

  • Anatomical structures like fibrous elements obstructing access to carpal tunnels are highlighted.
  • The presence of ligaments like the flexor retinaculum that enclose superficial carpal tunnel areas is explained.

Understanding Wrist Structures

This segment focuses on dissecting wrist structures to reveal deeper layers within carpal regions.

Dissection Insights

  • Nervous elements like palmar nerves are mentioned alongside structural components like flexor retinaculum.
  • Detailed instructions on removing flexor retinaculum to access carpal tunnels properly are provided.

Exploring Carpal Tunnel

Delving into visualizing carpal tunnel components post-dissection for a comprehensive understanding.

Carpal Tunnel Visualization

  • Post-retinaculum removal reveals clear views of structures like median nerve within carpal tunnels.

Anatomy Lecture Details

In this section of the anatomy lecture, the speaker delves into the detailed structures and boundaries of the carpal tunnel, highlighting key components such as arteries, veins, and nerves within this anatomical region.

Flexor Retinaculum and Carpal Tunnel Boundaries

  • The flexor retinaculum closes off the carpal tunnel both anteriorly and posteriorly. Remember that these structures define the limits of the carpal tunnel.

Structures in the Posterior Region of Carpus

  • Moving towards the posterior region of the carpus, one encounters numerous tendinous elements transitioning from the front to back of the hand. These tendons run through various fibrous sheaths.

Description of Tendon Sheaths in Carpus

  • Starting laterally and moving medially, several tendon sheaths can be identified in the wrist region. These include those formed by muscles like abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, among others.

Correlating Tendons with Specific Muscles

  • The first tendon sheath encountered is notably tough and comprises tendons from abductor pollicis longus and extensor pollicis brevis. Subsequent sheaths house tendons from radial wrist extensors before progressing to individual tendons like extensor pollicis longus.

Identification of Various Tendon Sheaths

  • Continuing medially reveals tendon sheaths housing muscles like extensor digitorum and extensor indicis before reaching those for extensor digiti minimi. The final sheath accommodates extensor carpi ulnaris muscle tendon.

New Section

In this section, the speaker discusses the formation of different structures within the hand.

Formation of Hand Structures

  • The first plane consists of the abductor pollicis brevis muscle, instrumented with a clamp and tied to the superficial branch of the radial artery. This forms part of the thenar compartment.
  • The superficial arch may not always be formed by both the ulnar and radial arteries. The second plane includes the superficial portion of the flexor pollicis brevis muscle and deeper adductor pollicis muscle.
  • The thenar compartment's second plane comprises the opponens pollicis, superficial portion of flexor pollicis brevis, and recurrent branch providing innervation to this region. The third plane involves the deep portion of flexor pollicis brevis.

New Section

This section delves into additional structures within the hand anatomy.

Further Hand Anatomy Details

  • The deep portion of flexor pollicis brevis is essential in forming the fourth plane along with adductor pollicis muscle and radial artery for vascular supply.
  • Exploring deeper regions, it is noted that the radial artery penetrates into deeper spaces for further analysis in subsequent sections.

New Section

Here, a discussion on specific muscles forming various planes within hand compartments takes place.

Muscles in Hand Compartments

  • Within hypothenar compartment's first plane lies abductor digiti minimi and flexor digiti minimi muscles. In contrast, only abductor digiti minimi constitutes the second plane. The third plane includes deep branches from ulnar artery and nerve directed laterally towards interossei muscles.