general features and attachments of typical ribs & atypical ribs
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General Features And Attachments Of Typical Ribs & Atypical Ribs. DR. RASHIDA MEMON. General Features And Attachments Of Typical Ribs Classification of Ribs Twelve pairs of ribs, each terminating anteriorly in a costal cartilage Classification of Ribs True Ribs: - PowerPoint PPT PresentationTRANSCRIPT
General Features And Attachments Of Typical Ribs & Atypical Ribs
DR. RASHIDA MEMON
General Features And Attachments Of Typical Ribs
Classification of Ribs Twelve pairs of ribs, each terminating anteriorly in a
costal cartilage Classification of RibsTrue Ribs: Costal cartilages of the upper seven ribs articulate
directly with the sternum, known as TRUE RIBS.False Ribs: Costal cartilages lower five do not
articulate directly to the sternum called as FALSE RIBS.
Floating ribs: Ribs 11th and 12th have no anterior connection with
other ribs or with the sternum
Costal Margin:
Costal cartilages of 8th to 10th ribs articulate anteriorly with costal cartilages of the ribs above, (like 8th articulates with 8th and so on) forming a continuous margin, Costal Margin.
Typical RibsThe Ribs 3rd to 9th or 10th have similar
features and called as TYPICAL RIBS
Consists of:Three parts :A curved shaft with anterior and posterior
ends. Anterior end is continuous with its costal
cartilage.Posterior end articulates with the vertebral
column and is characterized by a head, neck, and tubercle.
Head of RibHead is somewhat expanded. On its posterior end there are two articular
surfaces separated by crest. Smaller superior surface articulates with
inferior costal facet on body of vertebra aboveWhile larger inferior facet articulates with
superior costal facet of its own vertebra.
Neck of Rib Short flat region of bone. Separates the head from the tubercle.
Tubercle of ribProjects posteriorly from the junction of the neck
with the shaft.Consists of two regions An articular part and A non-articular part.
1. Articular part: It is medial. Has an oval facet for articulation with a
corresponding facet on the transverse process of the associated vertebra
2. Non-articular part:Raised non-articular part is roughened by
ligament attachments.
Shaft of Rib Shaft is generally thin and flat.Has two borders.Two surfaces.Borders: Upper Border Lower Border Surfaces: Outer Surface Inner Surface Superior margin is smooth and rounded, Inferior margin is sharp.Inferior margin of internal surface of shaft extends
beyond the limit of bone, called as costal groove.
Shaft of RibBeyond the tubercle the shaft of rib bends
on itself, known as costal angle. Along its long axis the shaft of ribs gently
twisted, this can be visible when rib placed on the table. This is helpful in respiration.
Attachments on Typical Ribs Provide attachment to intercostal muscles, Muscles between ribs
External Intercostal Muscles
Internal Intercostals Muscle
Innermost Intercostal Muscles
Innermost Intercostal Muscle
Transversus Thoracis
Subcostales
General Features and attachment of Atypical Ribs
Ribs having dissimilar features are the Atypical ribs.
These are 1st, 2nd, 10th, 11th and 12th.
1st Rib The 1st rib is: The broadest (i.e., Its body is widest and nearly
horizontal), Shortest, and Most sharply curved of the seven true ribs.Has a single facet on its head for articulation with
the t1 vertebra only.In comparison of typical rib the first rib has outer
and inner borders and superior and inferior surfaces On its superior has two transversely directed grooves
crossing for the subclavian vessels; Grooves are separated by a scalene tubercle and
ridge, to which the anterior scalene muscle is attached.
2nd Rib More typical Body is thinner, less curved, and
substantially longer than the 1st rib. Head has two facets for articulation with
the bodies of the T1 and T2 vertebraeMain atypical feature is a rough area on its
upper surface, The tuberosity for serratus anterior, from
which part of that muscle originates.
10th RibHead of rib tenth has a single facet for
articulation with its own vertebra.
11th & 12th Ribs 11 and 12 Ribs articulate only with the bodies of their own vertebrae and have no tubercles or necks.
Both ribs are short, have little curve, and are pointed anteriorly.
Anterior ends are free and covered with costal cartilages