Comp vert anatomy lab

Lab 1

Two types of vertebrae that make up the shark’s vertebral column

Trunk and caudal

What is the shape and structure of a shark’s vertebral centrum

Cylindrical and biconcave (amphicoelous)

Vertebral centrum

The thick, solid front part of a vertebra that forms the main vertebral body

Notochord

A flexible, cylindrical structure found in the embryos of all chordates

Chordate key characteristic

Notochord, a nerve tube along the back that becomes the central nervous system, openings in the pharynx used for filter feeding

Foramen

Natural opening, hole or passage found in bones

Which foramen allows the passage of the dorsal root of a spinal nerve

Intervertebral foramen

What structure extends ventrally from the centrum in caudal vertebrae

The hemal arch which terminates in a hemal spine

What are basapophyses and what attaches to them

Short ventrolateral projections on trunk centra (homologous to the base of hemal arches) that articulate with short cartilaginous ribs

What structures are located between the basapophyses of adjacent trunk vertebrae

Very small triangular ventral intercalary plates

Heterocercal caudal fin

A tail type with two unequal lobes (larger dorsal lobe, smaller ventral lobe) where the vertebral column tilts upward

Ceratotrichia

Fibrous fin rays that extend into and stiffen the fin web on the caudal and dorsal fins

Dorsal Fin Spines

Protective skeletal spines that precede each of the dorsal fins (anterior and posterior)

Basal Pterygiophore

A large, proximal cartilaginous skeletal element that supports the bases of each dorsal fin

Caudal fin skeletal support

Elongated neural and hemal arches paired with fibrous ceratotrichia stiffening the fin web

Dorsal root Foramen

The opening located in each dorsal intercalary plate for the passage of the dorsal root of a spinal nerve

Ventral Root foramen

The opening located in each neural plate/arch for the passage of the ventral root of a spinal nerve

Scapulocoracoid bar

The U-shaped skeletal complex forming the pectoral girdle, situated just posterior to the last gill slit

Coracoid Bar

The ventral portion of the U-shaped scapulocoracoid bar

Scapular Cartilage

The dorsal, distal part of the pectoral girdle that articulates with the pectoral fin

Glenoid surface

The dorsolateral smooth surface on the scapular cartilage that accommodates articulation of the pectoral fin

Suprascapular Cartilage

A small attenuated medially curved structure articulating dorsally with the scapular cartilage to complete the U of the pectoral girdle

Propterygium

The anterior basal pterygiophore supporting the proximal end of the pectoral fin (also found in pelvic fins)

Mesopterygium

The middle basal pterygiophore supporting the proximal end of the pectoral fin

Metapterygium

The posterior (or elongated) basal pterygiophore supporting the proximal end of pectoral and pelvic fins

Radial Pterygiophores

Rows of cartilages articulating with and radiating from the basal pterygiophores to form the major support of the fin

Puboischiadic bar

The short, horizontal bar forming the pelvic girdle, located just anterior to the cloaca

Iliac Processes

Small processes projecting from the anterior ends of the puboischiadic bar.

Acetabular surface

A smooth surface on the posterolateral aspect of the puboischiadic bar where the pelvic fins articulate.

Clasper

A modified sperm transfer organ present on the pelvic fins of male sharks, supported by cartilages derived from radial pterygiophores.

Splenial

A dermal bone on the medial surface of the mandible in Necturus

Atlas/Cervical

The single first vertebra that articulates with the two occipital condyles of the skull, allowing head movement independent of the vertebral column

Occipital condyles

Paired bony projections on the posterior aspect of the skull that articulate with the atlas

Neural arches

Arches arising dorsally from the centrum to form the vertebral canal housing the spinal cord

Neural spines

A process projecting posteriorly from the neural arch of a vertebra.

Prezygapophyses

A pair of anteriorly located articular processes on the neural arch that overlap with the postzygapophyses of an anterior adjacent vertebra to reduce vertical bending.

Postzygapophyses

A pair of articular processes projecting from the posterior end of the neural arch that articulate with prezygapophyses.

Transverse process

A caudally projecting process consisting of a dorsal diapophysis and a ventral parapophysis where ribs articulate

Diapophysis

The dorsal portion of the transverse process arising from the neural arch.

Parapophysis

The ventral portion of the transverse process arising from the centrum.

Caudal vertebrae

Vertebrae following the sacral region that lack ribs, feature prominent neural spines, and have a ventral hemal arch with a spine.

Hemal arch

An arch with a spine attached to the ventral surface of the caudal centrum through which the caudal artery and vein pass.

Ribs (Bicipital ribs)

Two-headed tetrapod ribs that articulate with the transverse processes of the trunk vertebrae.

Sternum

A breastbone structure that is absent as a solid element in Necturus, though small cartilage pieces embedded in the thoracic myosepta may represent it.

Coracoids

Broad plates of cartilage that project medially to overlap in the midline of the pectoral girdle.

Coracoid foramen

An opening piercing the coracoid plate that permits the passage of blood vessels and nerves.

Procoracoid

An ossified element projecting dorsally from the rim of the glenoid fossa with a distal suprascapular cartilage.

Suprascapular cartilage

A distal cartilaginous structure projecting dorsally from the ossified scapula.

Glenoid fossa

The depression on the pectoral girdle with which the head of the humerus articulates.

Brachium

The upper arm segment of the forelimb containing a single bone, the humerus.

Antebrachium

The forearm segment containing two bones: the medial radius and the lateral ulna.

Manus

The wrist and hand segment of the forelimb, consisting of the carpus, metacarpals, and phalanges terminating in four digits.

Humerus

The single bone found in the brachium (upper arm).

Radius

The medial bone of the antebrachium (forearm).

Ulna

The lateral bone of the antebrachium (forearm).

Carpus

The proximal portion of the manus (wrist) consisting of six small bones arranged in three rows, serving as the distal point of flexure.

Metacarpals

The intermediate series of bones in the manus, with one metacarpal per digit.

Phalanges

The distal bones of the digits

Pubis

The anterior cartilaginous element of the pelvic girdle that projects anteriorly and is pierced by the obturator foramen.

Ischium

The bony, posteriorly projecting element of the pelvic girdle.

Ilium (Ilia)

The dorsal bone of the pelvic girdle that extends to articulate with the modified rib of the sacral vertebra.

Acetabulum

The depression at the junction of the pubis, ischium, and ilium that accommodates the head of the femur.

Puboischiadic plate

The ventral plate formed by the medioventral symphysis of the paired anterior cartilaginous pubes and posterior bony ischia.

Obturator foramen

An opening piercing the pubis to permit the passage of the obturator nerve.

Pelvic canal

The space enclosed by the pelvic girdle that permits digestive and urogenital organs to access the cloaca.

Thigh

The upper leg segment containing a single bone, the femur.

Shank

The lower leg segment containing the tibia and fibula.

Pes

The foot segment of the hindlimb, consisting of the tarsus (ankle), metatarsals, and phalanges terminating in four digits.

Femur

The single bone occurring in the thigh (upper leg) that articulates proximally with the acetabulum.

Genu

The proximal portion of the pes (ankle), consisting of six small tarsal bones in three rows that articulate with the shank.

Hallux

The medial bone of the shank (lower leg). Big toe.

Fibula

The lateral bone of the shank (lower leg).

Tarsals

The six small bones arranged in three rows within the tarsus (ankle).

Metatarsals

The intermediate series of bones in the pes.

Tympanohyal

The most dorsal element of the cranial horn of the hyoid apparatus.

Stylohyal

A bony element of the cranial horn located ventral to the tympanohyal and dorsal to the epihyal.

Epihyal

A bony element of the cranial horn positioned between the stylohyal and the ceratohyal/body of the hyoid.

Cranial horn (Hyoid)

The anterior/cranial projection of the hyoid apparatus.

Caudal horn (Hyoid)

The posterior projection of the hyoid apparatus extending from the body (basihyal).

Body (Hyoid)

The central transverse portion of the hyoid apparatus that connects the cranial and caudal horns.

Lumbar vertebrae

The region of the vertebral column located in the lower back between the thoracic and sacral regions.

Caudal vertebrae

The vertebrae forming the tail region posterior to the sacrum.

Fibrocartilaginous intervertebral discs

Cushioning discs located between adjacent individual vertebrae in the mammalian column.

Centrum (Body)

The solid body of a vertebra forming the primary ventral support for the spinal cord.

Vertebral canal

The opening formed dorsally by the neural arch/laminae and ventrally by the centrum through which the spinal cord passes.

Demifacets

Articular facets occurring on the centrum of adjacent thoracic vertebrae that articulate with the capitulum of a rib.

Laminae

A pair of dorsal plates that complete the vertebral canal, whose dorsocaudal extensions form the spinous process.

Spinous process

The dorsocaudal projection formed by the fusion of the laminae, homologous with the neural spine.

Pedicles

A pair of bony segments extending between the laterally projecting transverse processes (diapophyses) and the centrum.

Transverse processes (Diapophyses)

Lateral projections on a vertebra; in thoracic vertebrae, their ventral surface bears an articular facet for the rib tuberculum.

Articular facet (Thoracic transverse process)

A smooth facet on the ventral surface of the transverse process that articulates with the tuberculum of a rib.

Transverse foramen

A characteristic opening passing through the transverse process of the first six cervical vertebrae in cats, transmitting the vertebral arteries and veins.

Atlantal foramen

The first intervertebral foramen located dorsal to the prezygapophysis of the atlas, through which the first spinal nerve and vertebral vein exit and the vertebral artery enters.

Odontoid process (dens)

A prominent cranial projection of the axis (formed by the fusion of the centrum of the atlas) flanked by prezygapophyses to articulate with the atlas.

Lumbar Vertebrae

The seven largest vertebrae in the cat, increasing in size caudally and featuring prominent pleurapophyses, accessory processes, and mammillary processes.

Pleurapophysis

A prominent, cranially projecting landmark on lumbar vertebrae representing a transverse process fused with an embryonic rib.

Accessory processes

Processes evident on all but the last two lumbar vertebrae that attach ligaments and muscles to stabilize the lower back against rotation.

Mammillary processes

Processes present on all lumbar vertebrae that work with accessory processes to attach stabilizing ligaments and muscles.

Sacrum

A complex of three fused vertebrae in the adult cat (decreasing in size caudally) that acts as a solid brace for the pelvic girdle.

Caudal Vertebrae

The vertebrae of the tail, being the smallest and most variable in number; more cranial caudal vertebrae show typical vertebral features, while more caudal ones resemble simple cylinders (centra).